Related
Suppose we are only given
var obj = {};
var propName = "foo.bar.foobar";
How can we set the property obj.foo.bar.foobar to a certain value (say "hello world")?
So I want to achieve this, while we only have the property name in a string:
obj.foo.bar.foobar = "hello world";
function assign(obj, prop, value) {
if (typeof prop === "string")
prop = prop.split(".");
if (prop.length > 1) {
var e = prop.shift();
assign(obj[e] =
Object.prototype.toString.call(obj[e]) === "[object Object]"
? obj[e]
: {},
prop,
value);
} else
obj[prop[0]] = value;
}
var obj = {},
propName = "foo.bar.foobar";
assign(obj, propName, "Value");
I know it's an old one, but I see only custom functions in answers.
If you don't mind using a library, look at lodash _.set and _.get function.
Since this question appears to be answered by incorrect answers, I'll just refer to the correct answer from a similar question
function setDeepValue(obj, value, path) {
if (typeof path === "string") {
var path = path.split('.');
}
if(path.length > 1){
var p=path.shift();
if(obj[p]==null || typeof obj[p]!== 'object'){
obj[p] = {};
}
setDeepValue(obj[p], value, path);
}else{
obj[path[0]] = value;
}
}
Use:
var obj = {};
setDeepValue(obj, 'Hello World', 'foo.bar.foobar');
edit: I've created a jsPerf.com testcase to compare the accepted answer with my version.
Turns out that my version is faster, especially when you go very deep.
http://jsfiddle.net/9YMm8/
var nestedObjectAssignmentFor = function(obj, propString, value) {
var propNames = propString.split('.'),
propLength = propNames.length-1,
tmpObj = obj;
for (var i = 0; i <= propLength ; i++) {
tmpObj = tmpObj[propNames[i]] = i !== propLength ? {} : value;
}
return obj;
}
var obj = nestedObjectAssignment({},"foo.bar.foobar","hello world");
All solutions overid any of the original data when setting so I have tweaked with the following, made it into a single object too:
var obj = {}
nestObject.set(obj, "a.b", "foo");
nestObject.get(obj, "a.b"); // returns foo
var nestedObject = {
set: function(obj, propString, value) {
var propNames = propString.split('.'),
propLength = propNames.length-1,
tmpObj = obj;
for (var i = 0; i <= propLength ; i++) {
if (i === propLength){
if(tmpObj[propNames[i]]){
tmpObj[propNames[i]] = value;
}else{
tmpObj[propNames[i]] = value;
}
}else{
if(tmpObj[propNames[i]]){
tmpObj = tmpObj[propNames[i]];
}else{
tmpObj = tmpObj[propNames[i]] = {};
}
}
}
return obj;
},
get: function(obj, propString){
var propNames = propString.split('.'),
propLength = propNames.length-1,
tmpObj = obj;
for (var i = 0; i <= propLength ; i++) {
if(tmpObj[propNames[i]]){
tmpObj = tmpObj[propNames[i]];
}else{
break;
}
}
return tmpObj;
}
};
Can also change functions to be an Oject.prototype method changing obj param to this:
Object.prototype = { setNested = function(){ ... }, getNested = function(){ ... } }
{}.setNested('a.c','foo')
Here is a get and set function i just compiled from a couple of threads + some custom code.
It will also create keys that don't exist on set.
function setValue(object, path, value) {
var a = path.split('.');
var o = object;
for (var i = 0; i < a.length - 1; i++) {
var n = a[i];
if (n in o) {
o = o[n];
} else {
o[n] = {};
o = o[n];
}
}
o[a[a.length - 1]] = value;
}
function getValue(object, path) {
var o = object;
path = path.replace(/\[(\w+)\]/g, '.$1');
path = path.replace(/^\./, '');
var a = path.split('.');
while (a.length) {
var n = a.shift();
if (n in o) {
o = o[n];
} else {
return;
}
}
return o;
}
Here is a simple function to do that using reference.
function setValueByPath (obj, path, value) {
var ref = obj;
path.split('.').forEach(function (key, index, arr) {
ref = ref[key] = index === arr.length - 1 ? value : {};
});
return obj;
}
You could split the path and make a check if the following element exist. If not assign an object to the new property.
Return then the value of the property.
At the end assign the value.
function setValue(object, path, value) {
var fullPath = path.split('.'),
way = fullPath.slice(),
last = way.pop();
way.reduce(function (r, a) {
return r[a] = r[a] || {};
}, object)[last] = value;
}
var object = {},
propName = 'foo.bar.foobar',
value = 'hello world';
setValue(object, propName, value);
console.log(object);
Here's one that returns the updated object
function deepUpdate(value, path, tree, branch = tree) {
const last = path.length === 1;
branch[path[0]] = last ? value : branch[path[0]];
return last ? tree : deepUpdate(value, path.slice(1), tree, branch[path[0]]);
}
const path = 'cat.dog';
const updated = deepUpdate('a', path.split('.'), {cat: {dog: null}})
// => { cat: {dog: 'a'} }
A very straightforward one.
This implementation should be very performant.
It avoids recursions, and function calls, while maintaining simplicity.
/**
* Set the value of a deep property, creating new objects as necessary.
* #param {Object} obj The object to set the value on.
* #param {String|String[]} path The property to set.
* #param {*} value The value to set.
* #return {Object} The object at the end of the path.
* #author github.com/victornpb
* #see https://stackoverflow.com/a/46060952/938822
* #example
* setDeep(obj, 'foo.bar.baz', 'quux');
*/
function setDeep(obj, path, value) {
const props = typeof path === 'string' ? path.split('.') : path;
for (var i = 0, n = props.length - 1; i < n; ++i) {
obj = obj[props[i]] = obj[props[i]] || {};
}
obj[props[i]] = value;
return obj;
}
/*********************** EXAMPLE ***********************/
const obj = {
hello : 'world',
};
setDeep(obj, 'root', true);
setDeep(obj, 'foo.bar.baz', 1);
setDeep(obj, ['foo','quux'], '😉');
console.log(obj);
// ⬇︎ Click "Run" below to see output
I was looking for an answer that does not overwrite existing values and was easily readable and was able to come up with this. Leaving this here in case it helps others with the same needs
function setValueAtObjectPath(obj, pathString, newValue) {
// create an array (pathComponents) of the period-separated path components from pathString
var pathComponents = pathString.split('.');
// create a object (tmpObj) that references the memory of obj
var tmpObj = obj;
for (var i = 0; i < pathComponents.length; i++) {
// if not on the last path component, then set the tmpObj as the value at this pathComponent
if (i !== pathComponents.length-1) {
// set tmpObj[pathComponents[i]] equal to an object of it's own value
tmpObj[pathComponents[i]] = {...tmpObj[pathComponents[i]]}
// set tmpObj to reference tmpObj[pathComponents[i]]
tmpObj = tmpObj[pathComponents[i]]
// else (IS the last path component), then set the value at this pathComponent equal to newValue
} else {
// set tmpObj[pathComponents[i]] equal to newValue
tmpObj[pathComponents[i]] = newValue
}
}
// return your object
return obj
}
Same as Rbar's answers, very useful when you're working with redux reducers. I use lodash clone instead of spread operator to support arrays too:
export function cloneAndPatch(obj, path, newValue, separator='.') {
let stack = Array.isArray(path) ? path : path.split(separator);
let newObj = _.clone(obj);
obj = newObj;
while (stack.length > 1) {
let property = stack.shift();
let sub = _.clone(obj[property]);
obj[property] = sub;
obj = sub;
}
obj[stack.shift()] = newValue;
return newObj;
}
Object.getPath = function(o, s) {
s = s.replace(/\[(\w+)\]/g, '.$1'); // convert indexes to properties
s = s.replace(/^\./, ''); // strip a leading dot
var a = s.split('.');
for (var i = 0, n = a.length; i < n; ++i) {
var k = a[i];
if (k in o) {
o = o[k];
} else {
return;
}
}
return o;
};
Object.setPath = function(o, p, v) {
var a = p.split('.');
var o = o;
for (var i = 0; i < a.length - 1; i++) {
if (a[i].indexOf('[') === -1) {
var n = a[i];
if (n in o) {
o = o[n];
} else {
o[n] = {};
o = o[n];
}
} else {
// Not totaly optimised
var ix = a[i].match(/\[.*?\]/g)[0];
var n = a[i].replace(ix, '');
o = o[n][ix.substr(1,ix.length-2)]
}
}
if (a[a.length - 1].indexOf('[') === -1) {
o[a[a.length - 1]] = v;
} else {
var ix = a[a.length - 1].match(/\[.*?\]/g)[0];
var n = a[a.length - 1].replace(ix, '');
o[n][ix.substr(1,ix.length-2)] = v;
}
};
Here's a simple method that uses a scoped Object that recursively set's the correct prop by path.
function setObjectValueByPath(pathScope, value, obj) {
const pathStrings = pathScope.split('/');
obj[pathStrings[0]] = pathStrings.length > 1 ?
setObjectValueByPath(
pathStrings.splice(1, pathStrings.length).join('/'),
value,
obj[pathStrings[0]]
) :
value;
return obj;
}
How about a simple and short one?
Object.assign(this.origin, { [propName]: value })
You can use reduce : (you can test it by copy/paste on browser console)
const setValueOf = (obj, value, ...path) => {
path.reduce((o, level, idx) => {
if(idx === path.length -1) { o[level] = value }; // on last change the value of the prop
return o && o[level]; // return the prop
}, obj);
};
Example
let objExmp = {a: 'a', b: {b1: 'b1', b2: 'b2', b3: { b3_3 : 'default_value' } }};
setValueOf(objExmp, 'new_value' , 'b', 'b3', 'b3_3');
console.log('objExmp', objExmp); // prop changed to 'new_value'
You can split the string path by '.' and spread like :
setValueOf(objExmp, 'new_value' , ...'b.b3.b3_3'.split('.'));
Suppose we are only given
var obj = {};
var propName = "foo.bar.foobar";
How can we set the property obj.foo.bar.foobar to a certain value (say "hello world")?
So I want to achieve this, while we only have the property name in a string:
obj.foo.bar.foobar = "hello world";
function assign(obj, prop, value) {
if (typeof prop === "string")
prop = prop.split(".");
if (prop.length > 1) {
var e = prop.shift();
assign(obj[e] =
Object.prototype.toString.call(obj[e]) === "[object Object]"
? obj[e]
: {},
prop,
value);
} else
obj[prop[0]] = value;
}
var obj = {},
propName = "foo.bar.foobar";
assign(obj, propName, "Value");
I know it's an old one, but I see only custom functions in answers.
If you don't mind using a library, look at lodash _.set and _.get function.
Since this question appears to be answered by incorrect answers, I'll just refer to the correct answer from a similar question
function setDeepValue(obj, value, path) {
if (typeof path === "string") {
var path = path.split('.');
}
if(path.length > 1){
var p=path.shift();
if(obj[p]==null || typeof obj[p]!== 'object'){
obj[p] = {};
}
setDeepValue(obj[p], value, path);
}else{
obj[path[0]] = value;
}
}
Use:
var obj = {};
setDeepValue(obj, 'Hello World', 'foo.bar.foobar');
edit: I've created a jsPerf.com testcase to compare the accepted answer with my version.
Turns out that my version is faster, especially when you go very deep.
http://jsfiddle.net/9YMm8/
var nestedObjectAssignmentFor = function(obj, propString, value) {
var propNames = propString.split('.'),
propLength = propNames.length-1,
tmpObj = obj;
for (var i = 0; i <= propLength ; i++) {
tmpObj = tmpObj[propNames[i]] = i !== propLength ? {} : value;
}
return obj;
}
var obj = nestedObjectAssignment({},"foo.bar.foobar","hello world");
All solutions overid any of the original data when setting so I have tweaked with the following, made it into a single object too:
var obj = {}
nestObject.set(obj, "a.b", "foo");
nestObject.get(obj, "a.b"); // returns foo
var nestedObject = {
set: function(obj, propString, value) {
var propNames = propString.split('.'),
propLength = propNames.length-1,
tmpObj = obj;
for (var i = 0; i <= propLength ; i++) {
if (i === propLength){
if(tmpObj[propNames[i]]){
tmpObj[propNames[i]] = value;
}else{
tmpObj[propNames[i]] = value;
}
}else{
if(tmpObj[propNames[i]]){
tmpObj = tmpObj[propNames[i]];
}else{
tmpObj = tmpObj[propNames[i]] = {};
}
}
}
return obj;
},
get: function(obj, propString){
var propNames = propString.split('.'),
propLength = propNames.length-1,
tmpObj = obj;
for (var i = 0; i <= propLength ; i++) {
if(tmpObj[propNames[i]]){
tmpObj = tmpObj[propNames[i]];
}else{
break;
}
}
return tmpObj;
}
};
Can also change functions to be an Oject.prototype method changing obj param to this:
Object.prototype = { setNested = function(){ ... }, getNested = function(){ ... } }
{}.setNested('a.c','foo')
Here is a get and set function i just compiled from a couple of threads + some custom code.
It will also create keys that don't exist on set.
function setValue(object, path, value) {
var a = path.split('.');
var o = object;
for (var i = 0; i < a.length - 1; i++) {
var n = a[i];
if (n in o) {
o = o[n];
} else {
o[n] = {};
o = o[n];
}
}
o[a[a.length - 1]] = value;
}
function getValue(object, path) {
var o = object;
path = path.replace(/\[(\w+)\]/g, '.$1');
path = path.replace(/^\./, '');
var a = path.split('.');
while (a.length) {
var n = a.shift();
if (n in o) {
o = o[n];
} else {
return;
}
}
return o;
}
Here is a simple function to do that using reference.
function setValueByPath (obj, path, value) {
var ref = obj;
path.split('.').forEach(function (key, index, arr) {
ref = ref[key] = index === arr.length - 1 ? value : {};
});
return obj;
}
You could split the path and make a check if the following element exist. If not assign an object to the new property.
Return then the value of the property.
At the end assign the value.
function setValue(object, path, value) {
var fullPath = path.split('.'),
way = fullPath.slice(),
last = way.pop();
way.reduce(function (r, a) {
return r[a] = r[a] || {};
}, object)[last] = value;
}
var object = {},
propName = 'foo.bar.foobar',
value = 'hello world';
setValue(object, propName, value);
console.log(object);
Here's one that returns the updated object
function deepUpdate(value, path, tree, branch = tree) {
const last = path.length === 1;
branch[path[0]] = last ? value : branch[path[0]];
return last ? tree : deepUpdate(value, path.slice(1), tree, branch[path[0]]);
}
const path = 'cat.dog';
const updated = deepUpdate('a', path.split('.'), {cat: {dog: null}})
// => { cat: {dog: 'a'} }
A very straightforward one.
This implementation should be very performant.
It avoids recursions, and function calls, while maintaining simplicity.
/**
* Set the value of a deep property, creating new objects as necessary.
* #param {Object} obj The object to set the value on.
* #param {String|String[]} path The property to set.
* #param {*} value The value to set.
* #return {Object} The object at the end of the path.
* #author github.com/victornpb
* #see https://stackoverflow.com/a/46060952/938822
* #example
* setDeep(obj, 'foo.bar.baz', 'quux');
*/
function setDeep(obj, path, value) {
const props = typeof path === 'string' ? path.split('.') : path;
for (var i = 0, n = props.length - 1; i < n; ++i) {
obj = obj[props[i]] = obj[props[i]] || {};
}
obj[props[i]] = value;
return obj;
}
/*********************** EXAMPLE ***********************/
const obj = {
hello : 'world',
};
setDeep(obj, 'root', true);
setDeep(obj, 'foo.bar.baz', 1);
setDeep(obj, ['foo','quux'], '😉');
console.log(obj);
// ⬇︎ Click "Run" below to see output
I was looking for an answer that does not overwrite existing values and was easily readable and was able to come up with this. Leaving this here in case it helps others with the same needs
function setValueAtObjectPath(obj, pathString, newValue) {
// create an array (pathComponents) of the period-separated path components from pathString
var pathComponents = pathString.split('.');
// create a object (tmpObj) that references the memory of obj
var tmpObj = obj;
for (var i = 0; i < pathComponents.length; i++) {
// if not on the last path component, then set the tmpObj as the value at this pathComponent
if (i !== pathComponents.length-1) {
// set tmpObj[pathComponents[i]] equal to an object of it's own value
tmpObj[pathComponents[i]] = {...tmpObj[pathComponents[i]]}
// set tmpObj to reference tmpObj[pathComponents[i]]
tmpObj = tmpObj[pathComponents[i]]
// else (IS the last path component), then set the value at this pathComponent equal to newValue
} else {
// set tmpObj[pathComponents[i]] equal to newValue
tmpObj[pathComponents[i]] = newValue
}
}
// return your object
return obj
}
Same as Rbar's answers, very useful when you're working with redux reducers. I use lodash clone instead of spread operator to support arrays too:
export function cloneAndPatch(obj, path, newValue, separator='.') {
let stack = Array.isArray(path) ? path : path.split(separator);
let newObj = _.clone(obj);
obj = newObj;
while (stack.length > 1) {
let property = stack.shift();
let sub = _.clone(obj[property]);
obj[property] = sub;
obj = sub;
}
obj[stack.shift()] = newValue;
return newObj;
}
Object.getPath = function(o, s) {
s = s.replace(/\[(\w+)\]/g, '.$1'); // convert indexes to properties
s = s.replace(/^\./, ''); // strip a leading dot
var a = s.split('.');
for (var i = 0, n = a.length; i < n; ++i) {
var k = a[i];
if (k in o) {
o = o[k];
} else {
return;
}
}
return o;
};
Object.setPath = function(o, p, v) {
var a = p.split('.');
var o = o;
for (var i = 0; i < a.length - 1; i++) {
if (a[i].indexOf('[') === -1) {
var n = a[i];
if (n in o) {
o = o[n];
} else {
o[n] = {};
o = o[n];
}
} else {
// Not totaly optimised
var ix = a[i].match(/\[.*?\]/g)[0];
var n = a[i].replace(ix, '');
o = o[n][ix.substr(1,ix.length-2)]
}
}
if (a[a.length - 1].indexOf('[') === -1) {
o[a[a.length - 1]] = v;
} else {
var ix = a[a.length - 1].match(/\[.*?\]/g)[0];
var n = a[a.length - 1].replace(ix, '');
o[n][ix.substr(1,ix.length-2)] = v;
}
};
Here's a simple method that uses a scoped Object that recursively set's the correct prop by path.
function setObjectValueByPath(pathScope, value, obj) {
const pathStrings = pathScope.split('/');
obj[pathStrings[0]] = pathStrings.length > 1 ?
setObjectValueByPath(
pathStrings.splice(1, pathStrings.length).join('/'),
value,
obj[pathStrings[0]]
) :
value;
return obj;
}
How about a simple and short one?
Object.assign(this.origin, { [propName]: value })
You can use reduce : (you can test it by copy/paste on browser console)
const setValueOf = (obj, value, ...path) => {
path.reduce((o, level, idx) => {
if(idx === path.length -1) { o[level] = value }; // on last change the value of the prop
return o && o[level]; // return the prop
}, obj);
};
Example
let objExmp = {a: 'a', b: {b1: 'b1', b2: 'b2', b3: { b3_3 : 'default_value' } }};
setValueOf(objExmp, 'new_value' , 'b', 'b3', 'b3_3');
console.log('objExmp', objExmp); // prop changed to 'new_value'
You can split the string path by '.' and spread like :
setValueOf(objExmp, 'new_value' , ...'b.b3.b3_3'.split('.'));
I have the string "presentation.launchBehavior.newWindow", which needs to be de-serialized into object:
var obj = {presentation: {launchBehavior: 'newWindow'}}
The last string after dot should be value, while other strings should be converted to strings. I've written the function to do that:
function des(obj, property, index, ar) {
var isLastCall = ar.length - 1 === index;
if (isLastCall) {
return;
}
var isNextLastCall = ar.length - 2 === index;
if (isNextLastCall) {
obj[property] = ar[ar.length - 1];
return obj;
} else {
obj[property] = {};
return obj[property];
}
}
var obj = {};
"presentation.launchBehavior.newWindow".split(".").reduce(des, obj);
obj.presentation.launchBehavior // newWindow
It's working, but I'd like to improve it to return the resulting object instead of having to create a variable outside the function. How can I do that? Maybe internals of the function can be improved as well.
You can use reduceRight:
const des = str => str.split(".").reduceRight( (prev, key) => ({[key]: prev}) );
console.log(des("presentation.launchBehavior.newWindow"));
Here is how I would do it.
function des(str) {
var props = (typeof str === "string") ? str.split('.') : str;
return props.length > 1 ? {[props[0]]: des(props.slice(1))}
: props[0];
}
console.log(des("presentation.launchBehavior.newWindow"));
It uses array computed properties (var o = {[key]: val}). It may not work on old browsers. For old browsers, you will have to first create the object assign then property (var o = {}; o[key] = val;).
Suppose we are only given
var obj = {};
var propName = "foo.bar.foobar";
How can we set the property obj.foo.bar.foobar to a certain value (say "hello world")?
So I want to achieve this, while we only have the property name in a string:
obj.foo.bar.foobar = "hello world";
function assign(obj, prop, value) {
if (typeof prop === "string")
prop = prop.split(".");
if (prop.length > 1) {
var e = prop.shift();
assign(obj[e] =
Object.prototype.toString.call(obj[e]) === "[object Object]"
? obj[e]
: {},
prop,
value);
} else
obj[prop[0]] = value;
}
var obj = {},
propName = "foo.bar.foobar";
assign(obj, propName, "Value");
I know it's an old one, but I see only custom functions in answers.
If you don't mind using a library, look at lodash _.set and _.get function.
Since this question appears to be answered by incorrect answers, I'll just refer to the correct answer from a similar question
function setDeepValue(obj, value, path) {
if (typeof path === "string") {
var path = path.split('.');
}
if(path.length > 1){
var p=path.shift();
if(obj[p]==null || typeof obj[p]!== 'object'){
obj[p] = {};
}
setDeepValue(obj[p], value, path);
}else{
obj[path[0]] = value;
}
}
Use:
var obj = {};
setDeepValue(obj, 'Hello World', 'foo.bar.foobar');
edit: I've created a jsPerf.com testcase to compare the accepted answer with my version.
Turns out that my version is faster, especially when you go very deep.
http://jsfiddle.net/9YMm8/
var nestedObjectAssignmentFor = function(obj, propString, value) {
var propNames = propString.split('.'),
propLength = propNames.length-1,
tmpObj = obj;
for (var i = 0; i <= propLength ; i++) {
tmpObj = tmpObj[propNames[i]] = i !== propLength ? {} : value;
}
return obj;
}
var obj = nestedObjectAssignment({},"foo.bar.foobar","hello world");
All solutions overid any of the original data when setting so I have tweaked with the following, made it into a single object too:
var obj = {}
nestObject.set(obj, "a.b", "foo");
nestObject.get(obj, "a.b"); // returns foo
var nestedObject = {
set: function(obj, propString, value) {
var propNames = propString.split('.'),
propLength = propNames.length-1,
tmpObj = obj;
for (var i = 0; i <= propLength ; i++) {
if (i === propLength){
if(tmpObj[propNames[i]]){
tmpObj[propNames[i]] = value;
}else{
tmpObj[propNames[i]] = value;
}
}else{
if(tmpObj[propNames[i]]){
tmpObj = tmpObj[propNames[i]];
}else{
tmpObj = tmpObj[propNames[i]] = {};
}
}
}
return obj;
},
get: function(obj, propString){
var propNames = propString.split('.'),
propLength = propNames.length-1,
tmpObj = obj;
for (var i = 0; i <= propLength ; i++) {
if(tmpObj[propNames[i]]){
tmpObj = tmpObj[propNames[i]];
}else{
break;
}
}
return tmpObj;
}
};
Can also change functions to be an Oject.prototype method changing obj param to this:
Object.prototype = { setNested = function(){ ... }, getNested = function(){ ... } }
{}.setNested('a.c','foo')
Here is a get and set function i just compiled from a couple of threads + some custom code.
It will also create keys that don't exist on set.
function setValue(object, path, value) {
var a = path.split('.');
var o = object;
for (var i = 0; i < a.length - 1; i++) {
var n = a[i];
if (n in o) {
o = o[n];
} else {
o[n] = {};
o = o[n];
}
}
o[a[a.length - 1]] = value;
}
function getValue(object, path) {
var o = object;
path = path.replace(/\[(\w+)\]/g, '.$1');
path = path.replace(/^\./, '');
var a = path.split('.');
while (a.length) {
var n = a.shift();
if (n in o) {
o = o[n];
} else {
return;
}
}
return o;
}
Here is a simple function to do that using reference.
function setValueByPath (obj, path, value) {
var ref = obj;
path.split('.').forEach(function (key, index, arr) {
ref = ref[key] = index === arr.length - 1 ? value : {};
});
return obj;
}
You could split the path and make a check if the following element exist. If not assign an object to the new property.
Return then the value of the property.
At the end assign the value.
function setValue(object, path, value) {
var fullPath = path.split('.'),
way = fullPath.slice(),
last = way.pop();
way.reduce(function (r, a) {
return r[a] = r[a] || {};
}, object)[last] = value;
}
var object = {},
propName = 'foo.bar.foobar',
value = 'hello world';
setValue(object, propName, value);
console.log(object);
Here's one that returns the updated object
function deepUpdate(value, path, tree, branch = tree) {
const last = path.length === 1;
branch[path[0]] = last ? value : branch[path[0]];
return last ? tree : deepUpdate(value, path.slice(1), tree, branch[path[0]]);
}
const path = 'cat.dog';
const updated = deepUpdate('a', path.split('.'), {cat: {dog: null}})
// => { cat: {dog: 'a'} }
A very straightforward one.
This implementation should be very performant.
It avoids recursions, and function calls, while maintaining simplicity.
/**
* Set the value of a deep property, creating new objects as necessary.
* #param {Object} obj The object to set the value on.
* #param {String|String[]} path The property to set.
* #param {*} value The value to set.
* #return {Object} The object at the end of the path.
* #author github.com/victornpb
* #see https://stackoverflow.com/a/46060952/938822
* #example
* setDeep(obj, 'foo.bar.baz', 'quux');
*/
function setDeep(obj, path, value) {
const props = typeof path === 'string' ? path.split('.') : path;
for (var i = 0, n = props.length - 1; i < n; ++i) {
obj = obj[props[i]] = obj[props[i]] || {};
}
obj[props[i]] = value;
return obj;
}
/*********************** EXAMPLE ***********************/
const obj = {
hello : 'world',
};
setDeep(obj, 'root', true);
setDeep(obj, 'foo.bar.baz', 1);
setDeep(obj, ['foo','quux'], '😉');
console.log(obj);
// ⬇︎ Click "Run" below to see output
I was looking for an answer that does not overwrite existing values and was easily readable and was able to come up with this. Leaving this here in case it helps others with the same needs
function setValueAtObjectPath(obj, pathString, newValue) {
// create an array (pathComponents) of the period-separated path components from pathString
var pathComponents = pathString.split('.');
// create a object (tmpObj) that references the memory of obj
var tmpObj = obj;
for (var i = 0; i < pathComponents.length; i++) {
// if not on the last path component, then set the tmpObj as the value at this pathComponent
if (i !== pathComponents.length-1) {
// set tmpObj[pathComponents[i]] equal to an object of it's own value
tmpObj[pathComponents[i]] = {...tmpObj[pathComponents[i]]}
// set tmpObj to reference tmpObj[pathComponents[i]]
tmpObj = tmpObj[pathComponents[i]]
// else (IS the last path component), then set the value at this pathComponent equal to newValue
} else {
// set tmpObj[pathComponents[i]] equal to newValue
tmpObj[pathComponents[i]] = newValue
}
}
// return your object
return obj
}
Same as Rbar's answers, very useful when you're working with redux reducers. I use lodash clone instead of spread operator to support arrays too:
export function cloneAndPatch(obj, path, newValue, separator='.') {
let stack = Array.isArray(path) ? path : path.split(separator);
let newObj = _.clone(obj);
obj = newObj;
while (stack.length > 1) {
let property = stack.shift();
let sub = _.clone(obj[property]);
obj[property] = sub;
obj = sub;
}
obj[stack.shift()] = newValue;
return newObj;
}
Object.getPath = function(o, s) {
s = s.replace(/\[(\w+)\]/g, '.$1'); // convert indexes to properties
s = s.replace(/^\./, ''); // strip a leading dot
var a = s.split('.');
for (var i = 0, n = a.length; i < n; ++i) {
var k = a[i];
if (k in o) {
o = o[k];
} else {
return;
}
}
return o;
};
Object.setPath = function(o, p, v) {
var a = p.split('.');
var o = o;
for (var i = 0; i < a.length - 1; i++) {
if (a[i].indexOf('[') === -1) {
var n = a[i];
if (n in o) {
o = o[n];
} else {
o[n] = {};
o = o[n];
}
} else {
// Not totaly optimised
var ix = a[i].match(/\[.*?\]/g)[0];
var n = a[i].replace(ix, '');
o = o[n][ix.substr(1,ix.length-2)]
}
}
if (a[a.length - 1].indexOf('[') === -1) {
o[a[a.length - 1]] = v;
} else {
var ix = a[a.length - 1].match(/\[.*?\]/g)[0];
var n = a[a.length - 1].replace(ix, '');
o[n][ix.substr(1,ix.length-2)] = v;
}
};
Here's a simple method that uses a scoped Object that recursively set's the correct prop by path.
function setObjectValueByPath(pathScope, value, obj) {
const pathStrings = pathScope.split('/');
obj[pathStrings[0]] = pathStrings.length > 1 ?
setObjectValueByPath(
pathStrings.splice(1, pathStrings.length).join('/'),
value,
obj[pathStrings[0]]
) :
value;
return obj;
}
How about a simple and short one?
Object.assign(this.origin, { [propName]: value })
You can use reduce : (you can test it by copy/paste on browser console)
const setValueOf = (obj, value, ...path) => {
path.reduce((o, level, idx) => {
if(idx === path.length -1) { o[level] = value }; // on last change the value of the prop
return o && o[level]; // return the prop
}, obj);
};
Example
let objExmp = {a: 'a', b: {b1: 'b1', b2: 'b2', b3: { b3_3 : 'default_value' } }};
setValueOf(objExmp, 'new_value' , 'b', 'b3', 'b3_3');
console.log('objExmp', objExmp); // prop changed to 'new_value'
You can split the string path by '.' and spread like :
setValueOf(objExmp, 'new_value' , ...'b.b3.b3_3'.split('.'));
Given the following form:
<form>
<input name="foo" value="bar">
<input name="hello" value="hello world">
</form>
I can use the $.param( .. ) construct to serialize the form:
$.param( $('form input') )
=> foo=bar&hello=hello+world
How can I deserialize the above String with JavaScript and get a hash back?
For example,
$.magicFunction("foo=bar&hello=hello+world")
=> {'foo' : 'bar', 'hello' : 'hello world'}
Reference: jQuery.param( obj ).
You should use jQuery BBQ's deparam function. It's well-tested and documented.
This is a slightly modified version of a function I wrote a while ago to do something similar.
var QueryStringToHash = function QueryStringToHash (query) {
var query_string = {};
var vars = query.split("&");
for (var i=0;i<vars.length;i++) {
var pair = vars[i].split("=");
pair[0] = decodeURIComponent(pair[0]);
pair[1] = decodeURIComponent(pair[1]);
// If first entry with this name
if (typeof query_string[pair[0]] === "undefined") {
query_string[pair[0]] = pair[1];
// If second entry with this name
} else if (typeof query_string[pair[0]] === "string") {
var arr = [ query_string[pair[0]], pair[1] ];
query_string[pair[0]] = arr;
// If third or later entry with this name
} else {
query_string[pair[0]].push(pair[1]);
}
}
return query_string;
};
How about this short functional approach?
function parseParams(str) {
return str.split('&').reduce(function (params, param) {
var paramSplit = param.split('=').map(function (value) {
return decodeURIComponent(value.replace(/\+/g, ' '));
});
params[paramSplit[0]] = paramSplit[1];
return params;
}, {});
}
Example:
parseParams("this=is&just=an&example") // Object {this: "is", just: "an", example: undefined}
My answer:
function(query){
var setValue = function(root, path, value){
if(path.length > 1){
var dir = path.shift();
if( typeof root[dir] == 'undefined' ){
root[dir] = path[0] == '' ? [] : {};
}
arguments.callee(root[dir], path, value);
}else{
if( root instanceof Array ){
root.push(value);
}else{
root[path] = value;
}
}
};
var nvp = query.split('&');
var data = {};
for( var i = 0 ; i < nvp.length ; i++ ){
var pair = nvp[i].split('=');
var name = decodeURIComponent(pair[0]);
var value = decodeURIComponent(pair[1]);
var path = name.match(/(^[^\[]+)(\[.*\]$)?/);
var first = path[1];
if(path[2]){
//case of 'array[level1]' || 'array[level1][level2]'
path = path[2].match(/(?=\[(.*)\]$)/)[1].split('][')
}else{
//case of 'name'
path = [];
}
path.unshift(first);
setValue(data, path, value);
}
return data;
}
I am using David Dorward's answer, and realized that it doesn't behave like PHP or Ruby on Rails how they parse the params:
1) a variable is only an array if it ends with [], such as ?choice[]=1&choice[]=12, not when it is ?a=1&a=2
2) when mulitple params exist with the same name, the later ones replaces the earlier ones, as on PHP servers (Ruby on Rails keep the first one and ignore the later ones), such as ?a=1&b=2&a=3
So modifying David's version, I have:
function QueryStringToHash(query) {
if (query == '') return null;
var hash = {};
var vars = query.split("&");
for (var i = 0; i < vars.length; i++) {
var pair = vars[i].split("=");
var k = decodeURIComponent(pair[0]);
var v = decodeURIComponent(pair[1]);
// If it is the first entry with this name
if (typeof hash[k] === "undefined") {
if (k.substr(k.length-2) != '[]') // not end with []. cannot use negative index as IE doesn't understand it
hash[k] = v;
else
hash[k.substr(0, k.length-2)] = [v];
// If subsequent entry with this name and not array
} else if (typeof hash[k] === "string") {
hash[k] = v; // replace it
// If subsequent entry with this name and is array
} else {
hash[k.substr(0, k.length-2)].push(v);
}
}
return hash;
};
which is tested fairly thoroughly.
I know this is an old thread, but maybe there is still some relevance in it?
Inspired by Jacky Li's good solution I tried a slight variation of my own with the objective to also be able to take care of arbitrary combinations of arrays and objects as input. I looked at how PHP would have done it and tried to get something "similar" going. Here is my code:
function getargs(str){
var ret={};
function build(urlnam,urlval,obj){ // extend the return object ...
var i,k,o=obj, x, rx=/\[([^\]]*)\]/g, idx=[urlnam.replace(rx,'')];
while (x=rx.exec(urlnam)) idx.push(x[1]);
while(true){
k=idx.shift();
if(k.trim()=='') {// key is empty: autoincremented index
if (o.constructor.name=='Array') k=o.length; // for Array
else if (o===obj ) {k=null} // for first level property name
else {k=-1; // for Object
for(i in o) if (+i>k) k=+i;
k++;
}
}
if(idx.length) {
// set up an array if the next key (idx[0]) appears to be
// numeric or empty, otherwise set up an object:
if (o[k]==null || typeof o[k]!='object') o[k]=isNaN(idx[0])?{}:[];
o=o[k]; // move on to the next level
}
else { // OK, time to store the urlval in its chosen place ...
// console.log('key',k,'val',urlval);
o[k]=urlval===""?null:urlval; break; // ... and leave the while loop.
}
}
return obj;
}
// ncnvt: is a flag that governs the conversion of
// numeric strings into numbers
var ncnvt=true,i,k,p,v,argarr=[],
ar=(str||window.location.search.substring(1)).split("&"),
l=ar.length;
for (i=0;i<l;i++) {if (ar[i]==="") continue;
p=ar[i].split("=");k=decodeURIComponent(p[0]);
v=p[1];v=(v!=null)?decodeURIComponent(v.replace(/\+/g,'%20')):'';
if (ncnvt && v.trim()>"" && !isNaN(v)) v-=0;
argarr.push([k,v]); // array: key-value-pairs of all arguments
}
for (i=0,l=argarr.length;i<l;i++) build(argarr[i][0],argarr[i][1],ret);
return ret;
}
If the function is called without the str-argument it will assume window.location.search.slice(1) as input.
Some examples:
['a=1&a=2', // 1
'x[y][0][z][]=1', // 2
'hello=[%22world%22]&world=hello', // 3
'a=1&a=2&&b&c=3&d=&=e&', // 4
'fld[2][]=2&fld[][]=3&fld[3][]=4&fld[]=bb&fld[]=cc', // 5
$.param({a:[[1,2],[3,4],{aa:'one',bb:'two'},[5,6]]}), // 6
'a[]=hi&a[]=2&a[3][]=7&a[3][]=99&a[]=13',// 7
'a[x]=hi&a[]=2&a[3][]=7&a[3][]=99&a[]=13'// 8
].map(function(v){return JSON.stringify(getargs(v));}).join('\n')
results in
{"a":2} // 1
{"x":{"y":[{"z":[1]}]}} // 2
{"hello":"[\"world\"]","world":"hello"} // 3
{"a":2,"b":null,"c":3,"d":null,"null":"e"} // 4 = { a: 2, b: null, c: 3, d: null, null: "e" }
{"fld":[null,null,[2],[3,4],"bb","cc"]} // 5
{"a":[[1,2],[3,4],{"aa":"one","bb":"two"},[5,6]]} // 6
{"a":["hi",2,null,[7,99],13]} // 7
{"a":{"0":2,"3":[7,99],"4":13,"x":"hi"}} // 8
Whereas Jacky Li's solution would produce the outer container for a as a plain object
{a:{"0":["1","2"],"1":["3","4"],"2":["5","6"]}} // 6: JackyLi's output
getargs() looks at the first given index for any level to determine whether this level will be an object (non-numeric index) or an array (numeric or empty), thus resulting in the output as shown in the listing bove (no. 6).
If the current object is an array then nulls get inserted wherever necessary to represent empty positions. Arrays are always consecutively numbered and 0-based).
Note, that in the example no. 8 the "autoincrement" for empty indices still works, even though we are dealing with an object now and not an array.
As far as I have tested it, my getargs() behaves pretty much identically to Chriss Roger's great jQuery $.deparam() plugin mentioned in the accepted answer. The main difference is that getargs runs without jQuery and that it does autoincrement in objects while $.deparam() will not do that:
JSON.stringify($.deparam('a[x]=hi&a[]=2&a[3][]=7&a[3][]=99&a[]=13').a);
results in
{"3":["7","99"],"x":"hi","undefined":"13"}
In $.deparam() the index [] is interpreted as an undefined instead of an autoincremented numerical index.
Here's how you could create a new jQuery function:
jQuery.unparam = function (value) {
var
// Object that holds names => values.
params = {},
// Get query string pieces (separated by &)
pieces = value.split('&'),
// Temporary variables used in loop.
pair, i, l;
// Loop through query string pieces and assign params.
for (i = 0, l = pieces.length; i < l; i++) {
pair = pieces[i].split('=', 2);
// Repeated parameters with the same name are overwritten. Parameters
// with no value get set to boolean true.
params[decodeURIComponent(pair[0])] = (pair.length == 2 ?
decodeURIComponent(pair[1].replace(/\+/g, ' ')) : true);
}
return params;
};
Thanks to him http://james.padolsey.com/javascript/parsing-urls-with-the-dom/
Pretty easy :D
function params_unserialize(p){
var ret = {},
seg = p.replace(/^\?/,'').split('&'),
len = seg.length, i = 0, s;
for (;i<len;i++) {
if (!seg[i]) { continue; }
s = seg[i].split('=');
ret[s[0]] = s[1];
}
return ret;}
This is really old question, but as i have coming - other people may coming to this post, and i want to a bit refresh this theme. Today no need to make custom solutions - there is URLSearchParams interface.
var paramsString = "q=URLUtils.searchParams&topic=api";
var searchParams = new URLSearchParams(paramsString);
//Iterate the search parameters.
for (let p of searchParams) {
console.log(p);
}
The only one limitation i know - this feature not supported in IE / Edge.
Here's my JavaScript implementation which I use in a server-side JScript ASP Classic page (demo):
// Transforms a query string in the form x[y][0][z][]=1 into {x:{y:[{z:[1]}]}}
function parseJQueryParams(p) {
var params = {};
var pairs = p.split('&');
for (var i=0; i<pairs.length; i++) {
var pair = pairs[i].split('=');
var indices = [];
var name = decodeURIComponent(pair[0]),
value = decodeURIComponent(pair[1]);
var name = name.replace(/\[([^\]]*)\]/g,
function(k, idx) { indices.push(idx); return ""; });
indices.unshift(name);
var o = params;
for (var j=0; j<indices.length-1; j++) {
var idx = indices[j];
var nextIdx = indices[j+1];
if (!o[idx]) {
if ((nextIdx == "") || (/^[0-9]+$/.test(nextIdx)))
o[idx] = [];
else
o[idx] = {};
}
o = o[idx];
}
idx = indices[indices.length-1];
if (idx == "") {
o.push(value);
}
else {
o[idx] = value;
}
}
return params;
}
I came up with this solution, which behaves like the .Net function HttpUtility.ParseQueryString.
In the result, the query string parameters are store in properties as lists of values, so that qsObj["param"] will be the same as calling GetValues("param") in .Net.
I hope you like it. JQuery not required.
var parseQueryString = function (querystring) {
var qsObj = new Object();
if (querystring) {
var parts = querystring.replace(/\?/, "").split("&");
var up = function (k, v) {
var a = qsObj[k];
if (typeof a == "undefined") {
qsObj[k] = [v];
}
else if (a instanceof Array) {
a.push(v);
}
};
for (var i in parts) {
var part = parts[i];
var kv = part.split('=');
if (kv.length == 1) {
var v = decodeURIComponent(kv[0] || "");
up(null, v);
}
else if (kv.length > 1) {
var k = decodeURIComponent(kv[0] || "");
var v = decodeURIComponent(kv[1] || "");
up(k, v);
}
}
}
return qsObj;
};
Here is how to use it:
var qsObj = parseQueryString("a=1&a=2&&b&c=3&d=&=e&");
To preview the result in the console juste type in:
JSON.stringify(qsObj)
Output:
"{"a":["1","2"],"null":["","b",""],"c":["3"],"d":[""],"":["e"]}"
There's a beautiful one-liner over at CSS-Tricks (original source from Nicholas Ortenzio):
function getQueryParameters(str) {
return (str || document.location.search).replace(/(^\?)/,'').split("&").map(function(n){return n = n.split("="),this[n[0]] = n[1],this}.bind({}))[0];
}
The really clever part is how it uses the anonymous function's this object, adding a key/value pair for each of the queries in the string. That said, there's some room for improvement. I've modified it a bit below, with the following changes:
Added handling of empty strings and non-string input.
Handled URI-encoded strings (%40->#, etc).
Removed the default use of document.location.search when the input was empty.
Changed the name, made it more readable, added comments.
function deparam(str) {
// Uses an empty 'this' to build up the results internally
function splitQuery(query) {
query = query.split('=').map(decodeURIComponent);
this[query[0]] = query[1];
return this;
}
// Catch bad input
if (!str || !(typeof str === 'string' || str instanceof String))
return {};
// Split the string, run splitQuery on each piece, and return 'this'
var queries = str.replace(/(^\?)/,'').split('&');
return queries.map(splitQuery.bind({}))[0];
}
use this :
// convert query string to json object
var queryString = "cat=3&sort=1&page=1";
queryString
.split("&")
.forEach((item) => {
const prop = item.split("=");
filter[prop[0]] = prop[1];
});
console.log(queryString);
This is my version in Coffeescript.
Also works for url like
http://localhost:4567/index.html?hello=[%22world%22]&world=hello#/home
getQueryString: (url)->
return null if typeof url isnt 'string' or url.indexOf("http") is -1
split = url.split "?"
return null if split.length < 2
path = split[1]
hash_pos = path.indexOf "#"
path = path[0...hash_pos] if hash_pos isnt -1
data = path.split "&"
ret = {}
for d in data
[name, val] = d.split "="
name = decodeURIComponent name
val = decodeURIComponent val
try
ret[name] = JSON.parse val
catch error
ret[name] = val
return ret
Here's a simple & compact one if you only want to quickly get the parameters from a GET request:
function httpGet() {
var a={},b,i,q=location.search.replace(/^\?/,"").split(/\&/);
for(i in q) if(q[i]) {b=q[i].split("=");if(b[0]) a[b[0]]=
decodeURIComponent(b[1]).replace(/\+/g," ");} return a;
}
It converts
something?aa=1&bb=2&cc=3
into an object like
{aa:1,bb:2,cc:3}
Creates a serialized representation of an array or object (can be used as URL query string for AJAX requests).
<button id='param'>GET</button>
<div id="show"></div>
<script>
$('#param').click(function () {
var personObj = new Object();
personObj.firstname = "vishal"
personObj.lastname = "pambhar";
document.getElementById('show').innerHTML=$.param(`personObj`));
});
</script>
output:firstname=vishal&lastname=pambhar
answers could use a bit of jQuery elegance:
(function($) {
var re = /([^&=]+)=?([^&]*)/g;
var decodeRE = /\+/g; // Regex for replacing addition symbol with a space
var decode = function (str) {return decodeURIComponent( str.replace(decodeRE, " ") );};
$.parseParams = function(query) {
var params = {}, e;
while ( e = re.exec(query) ) {
var k = decode( e[1] ), v = decode( e[2] );
if (k.substring(k.length - 2) === '[]') {
k = k.substring(0, k.length - 2);
(params[k] || (params[k] = [])).push(v);
}
else params[k] = v;
}
return params;
};
})(jQuery);
fork at https://gist.github.com/956897
You can use the function .serializeArray() (Link) of jQuery itself. This function returns an array of key-value pair. Result example:
[
{ name: "id", value: "1" },
{ name: "version", value: "100" }
]