Related
How do I remove all attributes which are undefined or null in a JavaScript object?
(Question is similar to this one for Arrays)
ES10/ES2019 examples
A simple one-liner (returning a new object).
let o = Object.fromEntries(Object.entries(obj).filter(([_, v]) => v != null));
Same as above but written as a function.
function removeEmpty(obj) {
return Object.fromEntries(Object.entries(obj).filter(([_, v]) => v != null));
}
This function uses recursion to remove items from nested objects.
function removeEmpty(obj) {
return Object.fromEntries(
Object.entries(obj)
.filter(([_, v]) => v != null)
.map(([k, v]) => [k, v === Object(v) ? removeEmpty(v) : v])
);
}
ES6/ES2015 examples
A simple one-liner. Warning: This mutates the given object instead of returning a new one.
Object.keys(obj).forEach((k) => obj[k] == null && delete obj[k]);
A single declaration (not mutating the given object).
let o = Object.keys(obj)
.filter((k) => obj[k] != null)
.reduce((a, k) => ({ ...a, [k]: obj[k] }), {});
Same as above but written as a function.
function removeEmpty(obj) {
return Object.entries(obj)
.filter(([_, v]) => v != null)
.reduce((acc, [k, v]) => ({ ...acc, [k]: v }), {});
}
This function uses recursion to remove items from nested objects.
function removeEmpty(obj) {
return Object.entries(obj)
.filter(([_, v]) => v != null)
.reduce(
(acc, [k, v]) => ({ ...acc, [k]: v === Object(v) ? removeEmpty(v) : v }),
{}
);
}
Same as the function above, but written in an imperative (non-functional) style.
function removeEmpty(obj) {
const newObj = {};
Object.entries(obj).forEach(([k, v]) => {
if (v === Object(v)) {
newObj[k] = removeEmpty(v);
} else if (v != null) {
newObj[k] = obj[k];
}
});
return newObj;
}
ES5/ES2009 examples
In the old days things were a lot more verbose.
This is a non recursive version written in a functional style.
function removeEmpty(obj) {
return Object.keys(obj)
.filter(function (k) {
return obj[k] != null;
})
.reduce(function (acc, k) {
acc[k] = obj[k];
return acc;
}, {});
}
This is a non recursive version written in an imperative style.
function removeEmpty(obj) {
const newObj = {};
Object.keys(obj).forEach(function (k) {
if (obj[k] && typeof obj[k] === "object") {
newObj[k] = removeEmpty(obj[k]);
} else if (obj[k] != null) {
newObj[k] = obj[k];
}
});
return newObj;
}
And a recursive version written in a functional style.
function removeEmpty(obj) {
return Object.keys(obj)
.filter(function (k) {
return obj[k] != null;
})
.reduce(function (acc, k) {
acc[k] = typeof obj[k] === "object" ? removeEmpty(obj[k]) : obj[k];
return acc;
}, {});
}
You can loop through the object:
var test = {
test1: null,
test2: 'somestring',
test3: 3,
}
function clean(obj) {
for (var propName in obj) {
if (obj[propName] === null || obj[propName] === undefined) {
delete obj[propName];
}
}
return obj
}
console.log(test);
console.log(clean(test));
If you're concerned about this property removal not running up object's proptype chain, you can also:
function clean(obj) {
var propNames = Object.getOwnPropertyNames(obj);
for (var i = 0; i < propNames.length; i++) {
var propName = propNames[i];
if (obj[propName] === null || obj[propName] === undefined) {
delete obj[propName];
}
}
}
A few notes on null vs undefined:
test.test1 === null; // true
test.test1 == null; // true
test.notaprop === null; // false
test.notaprop == null; // true
test.notaprop === undefined; // true
test.notaprop == undefined; // true
Shortest one liners for ES6+
Filter all falsy values ( "", 0, false, null, undefined )
Object.entries(obj).reduce((a,[k,v]) => (v ? (a[k]=v, a) : a), {})
Filter null and undefined values:
Object.entries(obj).reduce((a,[k,v]) => (v == null ? a : (a[k]=v, a)), {})
Filter ONLY null
Object.entries(obj).reduce((a,[k,v]) => (v === null ? a : (a[k]=v, a)), {})
Filter ONLY undefined
Object.entries(obj).reduce((a,[k,v]) => (v === undefined ? a : (a[k]=v, a)), {})
Recursive Solutions: Filters null and undefined
For Objects:
const cleanEmpty = obj => Object.entries(obj)
.map(([k,v])=>[k,v && typeof v === "object" ? cleanEmpty(v) : v])
.reduce((a,[k,v]) => (v == null ? a : (a[k]=v, a)), {});
For Objects and Arrays:
const cleanEmpty = obj => {
if (Array.isArray(obj)) {
return obj
.map(v => (v && typeof v === 'object') ? cleanEmpty(v) : v)
.filter(v => !(v == null));
} else {
return Object.entries(obj)
.map(([k, v]) => [k, v && typeof v === 'object' ? cleanEmpty(v) : v])
.reduce((a, [k, v]) => (v == null ? a : (a[k]=v, a)), {});
}
}
If you are using lodash or underscore.js, here is a simple solution:
var obj = {name: 'John', age: null};
var compacted = _.pickBy(obj);
This will only work with lodash 4, pre lodash 4 or underscore.js, use _.pick(obj, _.identity);
If somebody needs a recursive version of Owen's (and Eric's) answer, here it is:
/**
* Delete all null (or undefined) properties from an object.
* Set 'recurse' to true if you also want to delete properties in nested objects.
*/
function delete_null_properties(test, recurse) {
for (var i in test) {
if (test[i] === null) {
delete test[i];
} else if (recurse && typeof test[i] === 'object') {
delete_null_properties(test[i], recurse);
}
}
}
JSON.stringify removes the undefined keys.
removeUndefined = function(json){
return JSON.parse(JSON.stringify(json))
}
You can use a combination of JSON.stringify, its replacer parameter, and JSON.parse to turn it back into an object. Using this method also means the replacement is done to all nested keys within nested objects.
Example Object
var exampleObject = {
string: 'value',
emptyString: '',
integer: 0,
nullValue: null,
array: [1, 2, 3],
object: {
string: 'value',
emptyString: '',
integer: 0,
nullValue: null,
array: [1, 2, 3]
},
arrayOfObjects: [
{
string: 'value',
emptyString: '',
integer: 0,
nullValue: null,
array: [1, 2, 3]
},
{
string: 'value',
emptyString: '',
integer: 0,
nullValue: null,
array: [1, 2, 3]
}
]
};
Replacer Function
function replaceUndefinedOrNull(key, value) {
if (value === null || value === undefined) {
return undefined;
}
return value;
}
Clean the Object
exampleObject = JSON.stringify(exampleObject, replaceUndefinedOrNull);
exampleObject = JSON.parse(exampleObject);
CodePen example
Simplest possible Lodash solution to return an object with the null and undefined values filtered out.
_.omitBy(obj, _.isNil)
You can do a recursive removal in one line using json.stringify's replacer argument
const removeEmptyValues = obj => (
JSON.parse(JSON.stringify(obj, (k,v) => v ?? undefined))
)
Usage:
removeEmptyValues({a:{x:1,y:null,z:undefined}}) // Returns {a:{x:1}}
As mentioned in Emmanuel's comment, this technique only worked if your data structure contains only data types that can be put into JSON format (strings, numbers, lists, etc).
(This answer has been updated to use the new Nullish Coalescing operator. depending on browser support needs you may want to use this function instead: (k,v) => v!=null ? v : undefined)
You are probably looking for the delete keyword.
var obj = { };
obj.theProperty = 1;
delete obj.theProperty;
you can do shorter with ! condition
var r = {a: null, b: undefined, c:1};
for(var k in r)
if(!r[k]) delete r[k];
Remember in usage : as #semicolor announce in comments: This would also delete properties if the value is an empty string, false or zero
Remove all the properties with null and undefined
let obj = {
"id": 1,
"firstName": null,
"lastName": null,
"address": undefined,
"role": "customer",
"photo": "fb79fd5d-06c9-4097-8fdc-6cebf73fab26/fc8efe82-2af4-4c81-bde7-8d2f9dd7994a.jpg",
"location": null,
"idNumber": null,
};
let result = Object.entries(obj).reduce((a,[k,v]) => (v == null ? a : (a[k]=v, a)), {});
console.log(result)
I have same scenario in my project and achieved using following method.
It works with all data types, few mentioned above doesn't work with date and empty arrays .
removeEmptyKeysFromObject.js
removeEmptyKeysFromObject(obj) {
Object.keys(obj).forEach(key => {
if (Object.prototype.toString.call(obj[key]) === '[object Date]' && (obj[key].toString().length === 0 || obj[key].toString() === 'Invalid Date')) {
delete obj[key];
} else if (obj[key] && typeof obj[key] === 'object') {
this.removeEmptyKeysFromObject(obj[key]);
} else if (obj[key] == null || obj[key] === '') {
delete obj[key];
}
if (obj[key]
&& typeof obj[key] === 'object'
&& Object.keys(obj[key]).length === 0
&& Object.prototype.toString.call(obj[key]) !== '[object Date]') {
delete obj[key];
}
});
return obj;
}
pass any object to this function removeEmptyKeysFromObject()
Using ramda#pickBy you will remove all null, undefined and false values:
const obj = {a:1, b: undefined, c: null, d: 1}
R.pickBy(R.identity, obj)
As #manroe pointed out, to keep false values use isNil():
const obj = {a:1, b: undefined, c: null, d: 1, e: false}
R.pickBy(v => !R.isNil(v), obj)
Shorter ES6 pure solution, convert it to an array, use the filter function and convert it back to an object.
Would also be easy to make a function...
Btw. with this .length > 0 i check if there is an empty string / array, so it will remove empty keys.
const MY_OBJECT = { f: 'te', a: [] }
Object.keys(MY_OBJECT)
.filter(f => !!MY_OBJECT[f] && MY_OBJECT[f].length > 0)
.reduce((r, i) => { r[i] = MY_OBJECT[i]; return r; }, {});
JS BIN https://jsbin.com/kugoyinora/edit?js,console
Functional and immutable approach, without .filter and without creating more objects than needed
Object.keys(obj).reduce((acc, key) => (obj[key] === undefined ? acc : {...acc, [key]: obj[key]}), {})
Instead of delete the property, you can also create a new object with the keys that are not null.
const removeEmpty = (obj) => {
return Object.keys(obj).filter(key => obj[key]).reduce(
(newObj, key) => {
newObj[key] = obj[key]
return newObj
}, {}
)
}
For a deep search I used the following code, maybe it will be useful for anyone looking at this question (it is not usable for cyclic dependencies ) :
function removeEmptyValues(obj) {
for (var propName in obj) {
if (!obj[propName] || obj[propName].length === 0) {
delete obj[propName];
} else if (typeof obj[propName] === 'object') {
removeEmptyValues(obj[propName]);
}
}
return obj;
}
Here is a comprehensive recursive function (originally based on the one by #chickens) that will:
recursively remove what you tell it to defaults=[undefined, null, '', NaN]
Correctly handle regular objects, arrays and Date objects
const cleanEmpty = function(obj, defaults = [undefined, null, NaN, '']) {
if (!defaults.length) return obj
if (defaults.includes(obj)) return
if (Array.isArray(obj))
return obj
.map(v => v && typeof v === 'object' ? cleanEmpty(v, defaults) : v)
.filter(v => !defaults.includes(v))
return Object.entries(obj).length
? Object.entries(obj)
.map(([k, v]) => ([k, v && typeof v === 'object' ? cleanEmpty(v, defaults) : v]))
.reduce((a, [k, v]) => (defaults.includes(v) ? a : { ...a, [k]: v}), {})
: obj
}
USAGE:
// based off the recursive cleanEmpty function by #chickens.
// This one can also handle Date objects correctly
// and has a defaults list for values you want stripped.
const cleanEmpty = function(obj, defaults = [undefined, null, NaN, '']) {
if (!defaults.length) return obj
if (defaults.includes(obj)) return
if (Array.isArray(obj))
return obj
.map(v => v && typeof v === 'object' ? cleanEmpty(v, defaults) : v)
.filter(v => !defaults.includes(v))
return Object.entries(obj).length
? Object.entries(obj)
.map(([k, v]) => ([k, v && typeof v === 'object' ? cleanEmpty(v, defaults) : v]))
.reduce((a, [k, v]) => (defaults.includes(v) ? a : { ...a, [k]: v}), {})
: obj
}
// testing
console.log('testing: undefined \n', cleanEmpty(undefined))
console.log('testing: null \n',cleanEmpty(null))
console.log('testing: NaN \n',cleanEmpty(NaN))
console.log('testing: empty string \n',cleanEmpty(''))
console.log('testing: empty array \n',cleanEmpty([]))
console.log('testing: date object \n',cleanEmpty(new Date(1589339052 * 1000)))
console.log('testing: nested empty arr \n',cleanEmpty({ 1: { 2 :null, 3: [] }}))
console.log('testing: comprehensive obj \n', cleanEmpty({
a: 5,
b: 0,
c: undefined,
d: {
e: null,
f: [{
a: undefined,
b: new Date(),
c: ''
}]
},
g: NaN,
h: null
}))
console.log('testing: different defaults \n', cleanEmpty({
a: 5,
b: 0,
c: undefined,
d: {
e: null,
f: [{
a: undefined,
b: '',
c: new Date()
}]
},
g: [0, 1, 2, 3, 4],
h: '',
}, [undefined, null]))
Here's an alternative
Typescript:
function objectDefined <T>(obj: T): T {
const acc: Partial<T> = {};
for (const key in obj) {
if (obj[key] !== undefined) acc[key] = obj[key];
}
return acc as T;
}
Javascript:
function objectDefined(obj) {
const acc = {};
for (const key in obj) {
if (obj[key] !== undefined) acc[key] = obj[key];
}
return acc;
}
If you want 4 lines of a pure ES7 solution:
const clean = e => e instanceof Object ? Object.entries(e).reduce((o, [k, v]) => {
if (typeof v === 'boolean' || v) o[k] = clean(v);
return o;
}, e instanceof Array ? [] : {}) : e;
Or if you prefer more readable version:
function filterEmpty(obj, [key, val]) {
if (typeof val === 'boolean' || val) {
obj[key] = clean(val)
};
return obj;
}
function clean(entry) {
if (entry instanceof Object) {
const type = entry instanceof Array ? [] : {};
const entries = Object.entries(entry);
return entries.reduce(filterEmpty, type);
}
return entry;
}
This will preserve boolean values and it will clean arrays too. It also preserves the original object by returning a cleaned copy.
a reduce helper can do the trick (without type checking) -
const cleanObj = Object.entries(objToClean).reduce((acc, [key, value]) => {
if (value) {
acc[key] = value;
}
return acc;
}, {});
If you don't want to mutate in place, but return a clone with the null/undefined removed, you could use the ES6 reduce function.
// Helper to remove undefined or null properties from an object
function removeEmpty(obj) {
// Protect against null/undefined object passed in
return Object.keys(obj || {}).reduce((x, k) => {
// Check for null or undefined
if (obj[k] != null) {
x[k] = obj[k];
}
return x;
}, {});
}
To piggypack on Ben's answer on how to solve this problem using lodash's _.pickBy, you can also solve this problem in the sister library: Underscore.js's _.pick.
var obj = {name: 'John', age: null};
var compacted = _.pick(obj, function(value) {
return value !== null && value !== undefined;
});
See: JSFiddle Example
You can also use ... spread syntax using forEach something like this:
let obj = { a: 1, b: "b", c: undefined, d: null };
let cleanObj = {};
Object.keys(obj).forEach(val => {
const newVal = obj[val];
cleanObj = newVal ? { ...cleanObj, [val]: newVal } : cleanObj;
});
console.info(cleanObj);
If someone needs to remove undefined values from an object with deep search using lodash then here is the code that I'm using. It's quite simple to modify it to remove all empty values (null/undefined).
function omitUndefinedDeep(obj) {
return _.reduce(obj, function(result, value, key) {
if (_.isObject(value)) {
result[key] = omitUndefinedDeep(value);
}
else if (!_.isUndefined(value)) {
result[key] = value;
}
return result;
}, {});
}
With Lodash:
_.omitBy({a: 1, b: null}, (v) => !v)
If you use eslint and want to avoid tripping the the no-param-reassign rule, you can use Object.assign in conjunction with .reduce and a computed property name for a fairly elegant ES6 solution:
const queryParams = { a: 'a', b: 'b', c: 'c', d: undefined, e: null, f: '', g: 0 };
const cleanParams = Object.keys(queryParams)
.filter(key => queryParams[key] != null)
.reduce((acc, key) => Object.assign(acc, { [key]: queryParams[key] }), {});
// { a: 'a', b: 'b', c: 'c', f: '', g: 0 }
Here is a functional way to remove nulls from an Object using ES6 without mutating the object using only reduce:
const stripNulls = (obj) => {
return Object.keys(obj).reduce((acc, current) => {
if (obj[current] !== null) {
return { ...acc, [current]: obj[current] }
}
return acc
}, {})
}
Recursively remove null, undefined, empty objects and empty arrays, returning a copy (ES6 version)
export function skipEmpties(dirty) {
let item;
if (Array.isArray(dirty)) {
item = dirty.map(x => skipEmpties(x)).filter(value => value !== undefined);
return item.length ? item : undefined;
} else if (dirty && typeof dirty === 'object') {
item = {};
Object.keys(dirty).forEach(key => {
const value = skipEmpties(dirty[key]);
if (value !== undefined) {
item[key] = value;
}
});
return Object.keys(item).length ? item : undefined;
} else {
return dirty === null ? undefined : dirty;
}
}
I would like an array of objects with all object keys from a nested object. I wrote a recursive function to do this however at the point that the function is recalled it is not going through the object as expected but rather sending back an index infinitely.
let array = [];
const findKeys = (ob) => {
let id = 0;
let keys = Object.keys(ob);
for (let i = 0; i < keys.length; i++) {
let object = {
id: id,
label: keys[i],
};
array.push(object);
id ++;
findKeys(ob[keys[i]]);
}
return array;
};
let newArray = findKeys(data);
console.log(newArray);
example data structure:
const data = {a: {
b: {
c: {
foo: 'bar'
}
}
}}
You need to check to see if you have an object before you do the next recursive call. You also are resetting id so you are going to have the ids repeated (maybe you want that?) and you are using a global for the array so it can not be used more than once.
You are going to want something like:
function getKeys(obj) {
const array = [];
let id = 0;
function loop(obj) {
Object.entries(obj).forEach(entry => {
array.push({
id: ++id,
label: entry[0],
});
if(entry[1] != null && entry[1].constructor.name === "Object") {
loop(entry[1]);
}
});
}
loop(obj);
return array;
}
const obj1 = { a: 1, b: 'bar' };
console.log(getKeys(obj1));
const obj2 = { a: 1, b: { c: 'bar' } };
console.log(getKeys(obj2));
some thing like that
see also Check that value is object literal?
const data = { a: { b: { c: { foo: 'bar' } } }}
const isObject = el => (Object.prototype.toString.call(el) === '[object Object]')
const findKeys = obj =>
{
let arr = []
, id = 0
;
getKeys(obj)
return arr
function getKeys(o)
{
Object.keys(o).forEach(key =>
{
arr.push({ id:id++, label:key })
if (isObject(o[key]))
getKeys(o[key])
})
}
}
console.log( findKeys(data) )
.as-console-wrapper {max-height: 100%!important;top:0 }
Perhaps you may do like
var data = {a: {
b: {
c: {
foo: 'bar',
arr: [1,2,3,4]
}
}
}};
function getAllKeys(obj){
var keys = (typeof obj === "object") && (obj !== null) && Object.keys(obj);
return !!keys ? keys.reduce((r,k) => r.concat(getAllKeys(obj[k])),keys)
: [];
};
var res = getAllKeys(data);
console.log(JSON.stringify(res));
Here is a simple technique, using a fairly generic, depth-first, key-collecting traversal, followed by a mapping to add the indices:
const flattenKeys = (o) =>
Object (o) === o
? Object .entries (o) .flatMap (([k, v]) => [k, ...flattenKeys (v)])
: []
const getKeys = (o) =>
flattenKeys (o) .map ((label, id) => ({label, id}))
const data = {a: {b: {c: {foo: 'bar'}}}}
console .log (getKeys (data))
.as-console-wrapper {max-height: 100% !important; top: 0}
If you wanted a breadth-first traversal it wouldn't be much harder.
This separation of key collection and index generation makes the code much simpler to my mind.
I have a complex react state that is structured like this:
{
a: [
{
a: ['b','',]
}
],
b: {
a: ['b',''],
b: {c:'e',f:''}
},
c: 'd',
e: '',
f: ['g',''],
date: new Date()
}
As you can see, could be in the object a lot of empty strings. Before I submit it to the backend, I would like to iterate over the state object and remove all empty values. So I first need to deep clone the state not to mess with my applications state which can be done by:
clone = JSON.parse(JSON.stringify(state))
but how do I iterate over the clone and remove all empty strings?
You can pass a replacer function into your JSON.stringify() method. Returning undefined from the replacement function will remove the key-value pair, so you can return undefined when you encounter an empty string. Likewise, when you encounter an array, you can filter it to only contain values which are non-empty strings.
See example below:
const state = {
a: [{
a: ['b', '', ]
}],
b: {
a: ['b', ''],
b: {
c: 'e',
f: ''
}
},
c: 'd',
e: '',
f: ['g', ''],
h: {},
date: new Date()
};
const clone = JSON.parse(JSON.stringify(state, (key, value) => {
if (typeof value === 'string' && value === "" || Object(value) === value && Object.keys(value).length === 0) {
return undefined;
} else if(Array.isArray(value)) {
return value.filter(val => val !== "");
}
return value;
}));
console.log(clone);
You can also create a new object with a dedicated function that recursively removes the empty strings. Something like this:
const removeEmpties = (obj) =>
Array .isArray (obj)
? obj .filter (x => x !== '') .map (removeEmpties)
: Object (obj) === obj
? Object .fromEntries (Object .entries (obj)
.filter (([k, v]) => v !== '')
.map (([k, v]) => [k, removeEmpties (v)]
))
: obj
const input = {a: [{a: ['b','',]}], b: {a: ['b',''], b: {c:'e',f:''}}, c: 'd', e: '', f: ['g',''], date: new Date()}
console .log (removeEmpties (input))
.as-console-wrapper {min-height: 100% !important; top: 0}
But that could be generalized to a more reusable functionlike this:
const deepFilter = (pred) => (obj) =>
Array .isArray (obj)
? obj .filter (pred) .map (deepFilter (pred))
: Object (obj) === obj
? Object .fromEntries (Object .entries (obj)
.filter (([k, v]) => pred(v))
.map (([k, v]) => [k, deepFilter (pred) (v)]
))
: obj
And then specialized for your case this way:
const removeEmpties = deepFilter (x => x !== '')
I have a HUGE collection and I am looking for a property by key someplace inside the collection. What is a reliable way to get a list of references or full paths to all objects containing that key/index? I use jQuery and lodash if it helps and you can forget about infinite pointer recursion, this is a pure JSON response.
fn({ 'a': 1, 'b': 2, 'c': {'d':{'e':7}}}, "d");
// [o.c]
fn({ 'a': 1, 'b': 2, 'c': {'d':{'e':7}}}, "e");
// [o.c.d]
fn({ 'aa': 1, 'bb': 2, 'cc': {'d':{'x':9}}, dd:{'d':{'y':9}}}, 'd');
// [o.cc,o.cc.dd]
fwiw lodash has a _.find function that will find nested objects that are two nests deep, but it seems to fail after that. (e.g. http://codepen.io/anon/pen/bnqyh)
This should do it:
function fn(obj, key) {
if (_.has(obj, key)) // or just (key in obj)
return [obj];
// elegant:
return _.flatten(_.map(obj, function(v) {
return typeof v == "object" ? fn(v, key) : [];
}), true);
// or efficient:
var res = [];
_.forEach(obj, function(v) {
if (typeof v == "object" && (v = fn(v, key)).length)
res.push.apply(res, v);
});
return res;
}
a pure JavaScript solution would look like the following:
function findNested(obj, key, memo) {
var i,
proto = Object.prototype,
ts = proto.toString,
hasOwn = proto.hasOwnProperty.bind(obj);
if ('[object Array]' !== ts.call(memo)) memo = [];
for (i in obj) {
if (hasOwn(i)) {
if (i === key) {
memo.push(obj[i]);
} else if ('[object Array]' === ts.call(obj[i]) || '[object Object]' === ts.call(obj[i])) {
findNested(obj[i], key, memo);
}
}
}
return memo;
}
here's how you'd use this function:
findNested({'aa': 1, 'bb': 2, 'cc': {'d':{'x':9}}, dd:{'d':{'y':9}}}, 'd');
and the result would be:
[{x: 9}, {y: 9}]
this will deep search an array of objects (hay) for a value (needle) then return an array with the results...
search = function(hay, needle, accumulator) {
var accumulator = accumulator || [];
if (typeof hay == 'object') {
for (var i in hay) {
search(hay[i], needle, accumulator) == true ? accumulator.push(hay) : 1;
}
}
return new RegExp(needle).test(hay) || accumulator;
}
If you can write a recursive function in plain JS (or with combination of lodash) that will be the best one (by performance), but if you want skip recursion from your side and want to go for a simple readable code (which may not be best as per performance) then you can use lodash#cloneDeepWith for any purposes where you have to traverse a object recursively.
let findValuesDeepByKey = (obj, key, res = []) => (
_.cloneDeepWith(obj, (v,k) => {k==key && res.push(v)}) && res
)
So, the callback you passes as the 2nd argument of _.cloneDeepWith will recursively traverse all the key/value pairs recursively and all you have to do is the operation you want to do with each. the above code is just a example of your case. Here is a working example:
var object = {
prop1: 'ABC1',
prop2: 'ABC2',
prop3: {
prop4: 'ABC3',
prop5Arr: [{
prop5: 'XYZ'
},
{
prop5: 'ABC4'
},
{
prop6: {
prop6NestedArr: [{
prop1: 'XYZ Nested Arr'
},
{
propFurtherNested: {key100: '100 Value'}
}
]
}
}
]
}
}
let findValuesDeepByKey = (obj, key, res = []) => (
_.cloneDeepWith(obj, (v,k) => {k==key && res.push(v)}) && res
)
console.log(findValuesDeepByKey(object, 'prop1'));
console.log(findValuesDeepByKey(object, 'prop5'));
console.log(findValuesDeepByKey(object, 'key100'));
<script src="https://cdnjs.cloudflare.com/ajax/libs/lodash.js/4.17.10/lodash.min.js"></script>
With Deepdash you can pickDeep and then get paths from it, or indexate (build path->value object)
var obj = { 'aa': 1, 'bb': 2, 'cc': {'d':{'x':9}}, dd:{'d':{'y':9}}}
var cherry = _.pickDeep(obj,"d");
console.log(JSON.stringify(cherry));
// {"cc":{"d":{}},"dd":{"d":{}}}
var paths = _.paths(cherry);
console.log(paths);
// ["cc.d", "dd.d"]
paths = _.paths(cherry,{pathFormat:'array'});
console.log(JSON.stringify(paths));
// [["cc","d"],["dd","d"]]
var index = _.indexate(cherry);
console.log(JSON.stringify(index));
// {"cc.d":{},"dd.d":{}}
Here is a Codepen demo
Something like this would work, converting it to an object and recursing down.
function find(jsonStr, searchkey) {
var jsObj = JSON.parse(jsonStr);
var set = [];
function fn(obj, key, path) {
for (var prop in obj) {
if (prop === key) {
set.push(path + "." + prop);
}
if (obj[prop]) {
fn(obj[prop], key, path + "." + prop);
}
}
return set;
}
fn(jsObj, searchkey, "o");
}
Fiddle: jsfiddle
In case you don't see the updated answer from #eugene, this tweak allows for passing a list of Keys to search for!
// Method that will find any "message" in the Apex errors that come back after insert attempts
// Could be a validation rule, or duplicate record, or pagemessage.. who knows!
// Use in your next error toast from a wire or imperative catch path!
// message: JSON.stringify(this.findNested(error, ['message', 'stackTrace'])),
// Testing multiple keys: this.findNested({thing: 0, list: [{message: 'm'}, {stackTrace: 'st'}], message: 'm2'}, ['message', 'stackTrace'])
findNested(obj, keys, memo) {
let i,
proto = Object.prototype,
ts = proto.toString,
hasOwn = proto.hasOwnProperty.bind(obj);
if ('[object Array]' !== ts.call(memo)) memo = [];
for (i in obj) {
if (hasOwn(i)) {
if (keys.includes(i)) {
memo.push(obj[i]);
} else if ('[object Array]' === ts.call(obj[i]) || '[object Object]' === ts.call(obj[i])) {
this.findNested(obj[i], keys, memo);
}
}
}
return memo.length == 0 ? null : memo;
}
Here's how I did it:
function _find( obj, field, results )
{
var tokens = field.split( '.' );
// if this is an array, recursively call for each row in the array
if( obj instanceof Array )
{
obj.forEach( function( row )
{
_find( row, field, results );
} );
}
else
{
// if obj contains the field
if( obj[ tokens[ 0 ] ] !== undefined )
{
// if we're at the end of the dot path
if( tokens.length === 1 )
{
results.push( obj[ tokens[ 0 ] ] );
}
else
{
// keep going down the dot path
_find( obj[ tokens[ 0 ] ], field.substr( field.indexOf( '.' ) + 1 ), results );
}
}
}
}
Testing it with:
var obj = {
document: {
payload: {
items:[
{field1: 123},
{field1: 456}
]
}
}
};
var results = [];
_find(obj.document,'payload.items.field1', results);
console.log(results);
Outputs
[ 123, 456 ]
We use object-scan for data processing tasks. It's pretty awesome once you've wrapped your head around how to use it.
// const objectScan = require('object-scan');
const haystack = { a: { b: { c: 'd' }, e: { f: 'g' } } };
const r = objectScan(['a.*.*'], { joined: true, rtn: 'entry' })(haystack);
console.log(r);
// => [ [ 'a.e.f', 'g' ], [ 'a.b.c', 'd' ] ]
.as-console-wrapper {max-height: 100% !important; top: 0}
<script src="https://bundle.run/object-scan#13.8.0"></script>
Disclaimer: I'm the author of object-scan
There are plenty more examples on the website.
The shortest and simplest solution:
Array.prototype.findpath = function(item,path) {
return this.find(function(f){return item==eval('f.'+path)});
}
ECMAScript 5 has the filter() prototype for Array types, but not Object types, if I understand correctly.
How would I implement a filter() for Objects in JavaScript?
Let's say I have this object:
var foo = {
bar: "Yes"
};
And I want to write a filter() that works on Objects:
Object.prototype.filter = function(predicate) {
var result = {};
for (key in this) {
if (this.hasOwnProperty(key) && !predicate(this[key])) {
result[key] = this[key];
}
}
return result;
};
This works when I use it in the following demo, but when I add it to my site that uses jQuery 1.5 and jQuery UI 1.8.9, I get JavaScript errors in FireBug.
Object.prototype.filter = function(predicate) {
var result = {};
for (key in this) {
if (this.hasOwnProperty(key) && !predicate(this[key])) {
console.log("copying");
result[key] = this[key];
}
}
return result;
};
var foo = {
bar: "Yes",
moo: undefined
};
foo = foo.filter(function(property) {
return typeof property === "undefined";
});
document.getElementById('disp').innerHTML = JSON.stringify(foo, undefined, ' ');
console.log(foo);
#disp {
white-space: pre;
font-family: monospace
}
<div id="disp"></div>
First of all, it's considered bad practice to extend Object.prototype. Instead, provide your feature as stand-alone function, or if you really want to extend a global, provide it as utility function on Object, just like there already are Object.keys, Object.assign, Object.is, ...etc.
I provide here several solutions:
Using reduce and Object.keys
As (1), in combination with Object.assign
Using map and spread syntax instead of reduce
Using Object.entries and Object.fromEntries
1. Using reduce and Object.keys
With reduce and Object.keys to implement the desired filter (using ES6 arrow syntax):
Object.filter = (obj, predicate) =>
Object.keys(obj)
.filter( key => predicate(obj[key]) )
.reduce( (res, key) => (res[key] = obj[key], res), {} );
// Example use:
var scores = {
John: 2, Sarah: 3, Janet: 1
};
var filtered = Object.filter(scores, score => score > 1);
console.log(filtered);
Note that in the above code predicate must be an inclusion condition (contrary to the exclusion condition the OP used), so that it is in line with how Array.prototype.filter works.
2. As (1), in combination with Object.assign
In the above solution the comma operator is used in the reduce part to return the mutated res object. This could of course be written as two statements instead of one expression, but the latter is more concise. To do it without the comma operator, you could use Object.assign instead, which does return the mutated object:
Object.filter = (obj, predicate) =>
Object.keys(obj)
.filter( key => predicate(obj[key]) )
.reduce( (res, key) => Object.assign(res, { [key]: obj[key] }), {} );
// Example use:
var scores = {
John: 2, Sarah: 3, Janet: 1
};
var filtered = Object.filter(scores, score => score > 1);
console.log(filtered);
3. Using map and spread syntax instead of reduce
Here we move the Object.assign call out of the loop, so it is only made once, and pass it the individual keys as separate arguments (using the spread syntax):
Object.filter = (obj, predicate) =>
Object.assign(...Object.keys(obj)
.filter( key => predicate(obj[key]) )
.map( key => ({ [key]: obj[key] }) ) );
// Example use:
var scores = {
John: 2, Sarah: 3, Janet: 1
};
var filtered = Object.filter(scores, score => score > 1);
console.log(filtered);
4. Using Object.entries and Object.fromEntries
As the solution translates the object to an intermediate array and then converts that back to a plain object, it would be useful to make use of Object.entries (ES2017) and the opposite (i.e. create an object from an array of key/value pairs) with Object.fromEntries (ES2019).
It leads to this "one-liner" method on Object:
Object.filter = (obj, predicate) =>
Object.fromEntries(Object.entries(obj).filter(predicate));
// Example use:
var scores = {
John: 2, Sarah: 3, Janet: 1
};
var filtered = Object.filter(scores, ([name, score]) => score > 1);
console.log(filtered);
The predicate function gets a key/value pair as argument here, which is a bit different, but allows for more possibilities in the predicate function's logic.
Never ever extend Object.prototype.
Horrible things will happen to your code. Things will break. You're extending all object types, including object literals.
Here's a quick example you can try:
// Extend Object.prototype
Object.prototype.extended = "I'm everywhere!";
// See the result
alert( {}.extended ); // "I'm everywhere!"
alert( [].extended ); // "I'm everywhere!"
alert( new Date().extended ); // "I'm everywhere!"
alert( 3..extended ); // "I'm everywhere!"
alert( true.extended ); // "I'm everywhere!"
alert( "here?".extended ); // "I'm everywhere!"
Instead create a function that you pass the object.
Object.filter = function( obj, predicate) {
let result = {}, key;
for (key in obj) {
if (obj.hasOwnProperty(key) && !predicate(obj[key])) {
result[key] = obj[key];
}
}
return result;
};
Solution in Vanilla JS from year 2020.
let romNumbers={'I':1,'V':5,'X':10,'L':50,'C':100,'D':500,'M':1000}
You can filter romNumbers object by key:
const filteredByKey = Object.fromEntries(
Object.entries(romNumbers).filter(([key, value]) => key === 'I') )
// filteredByKey = {I: 1}
Or filter romNumbers object by value:
const filteredByValue = Object.fromEntries(
Object.entries(romNumbers).filter(([key, value]) => value === 5) )
// filteredByValue = {V: 5}
If you're willing to use underscore or lodash, you can use pick (or its opposite, omit).
Examples from underscore's docs:
_.pick({name: 'moe', age: 50, userid: 'moe1'}, 'name', 'age');
// {name: 'moe', age: 50}
Or with a callback (for lodash, use pickBy):
_.pick({name: 'moe', age: 50, userid: 'moe1'}, function(value, key, object) {
return _.isNumber(value);
});
// {age: 50}
ES6 approach...
Imagine you have this object below:
const developers = {
1: {
id: 1,
name: "Brendan",
family: "Eich"
},
2: {
id: 2,
name: "John",
family: "Resig"
},
3: {
id: 3,
name: "Alireza",
family: "Dezfoolian"
}
};
Create a function:
const filterObject = (obj, filter, filterValue) =>
Object.keys(obj).reduce((acc, val) =>
(obj[val][filter] === filterValue ? acc : {
...acc,
[val]: obj[val]
}
), {});
And call it:
filterObject(developers, "name", "Alireza");
and will return:
{
1: {
id: 1,
name: "Brendan",
family: "Eich"
},
2: {
id: 2,
name: "John",
family: "Resig"
}
}
As patrick already stated this is a bad idea, as it will almost certainly break any 3rd party code you could ever wish to use.
All libraries like jquery or prototype will break if you extend Object.prototype, the reason being that lazy iteration over objects (without hasOwnProperty checks) will break since the functions you add will be part of the iteration.
Given
object = {firstname: 'abd', lastname:'tm', age:16, school:'insat'};
keys = ['firstname', 'age'];
then :
keys.reduce((result, key) => ({ ...result, [key]: object[key] }), {});
// {firstname:'abd', age: 16}
// Helper
function filter(object, ...keys) {
return keys.reduce((result, key) => ({ ...result, [key]: object[key] }), {});
};
//Example
const person = {firstname: 'abd', lastname:'tm', age:16, school:'insat'};
// Expected to pick only firstname and age keys
console.log(
filter(person, 'firstname', 'age')
)
Plain ES6:
var foo = {
bar: "Yes"
};
const res = Object.keys(foo).filter(i => foo[i] === 'Yes')
console.log(res)
// ["bar"]
How about:
function filterObj(keys, obj) {
const newObj = {};
for (let key in obj) {
if (keys.includes(key)) {
newObj[key] = obj[key];
}
}
return newObj;
}
Or...
function filterObj(keys, obj) {
const newObj = {};
Object.keys(obj).forEach(key => {
if (keys.includes(key)) {
newObj[key] = obj[key];
}
});
return newObj;
}
I have created an Object.filter() which does not only filter by a function, but also accepts an array of keys to include. The optional third parameter will allow you to invert the filter.
Given:
var foo = {
x: 1,
y: 0,
z: -1,
a: 'Hello',
b: 'World'
}
Array:
Object.filter(foo, ['z', 'a', 'b'], true);
Function:
Object.filter(foo, function (key, value) {
return Ext.isString(value);
});
Code
Disclaimer: I chose to use Ext JS core for brevity. Did not feel it was necessary to write type checkers for object types as it was not part of the question.
// Helper function
function print(obj) {
document.getElementById('disp').innerHTML += JSON.stringify(obj, undefined, ' ') + '<br />';
console.log(obj);
}
Object.filter = function (obj, ignore, invert) {
let result = {}; // Returns a filtered copy of the original list
if (ignore === undefined) {
return obj;
}
invert = invert || false;
let not = function(condition, yes) { return yes ? !condition : condition; };
let isArray = Ext.isArray(ignore);
for (var key in obj) {
if (obj.hasOwnProperty(key) &&
!(isArray && not(!Ext.Array.contains(ignore, key), invert)) &&
!(!isArray && not(!ignore.call(undefined, key, obj[key]), invert))) {
result[key] = obj[key];
}
}
return result;
};
let foo = {
x: 1,
y: 0,
z: -1,
a: 'Hello',
b: 'World'
};
print(Object.filter(foo, ['z', 'a', 'b'], true));
print(Object.filter(foo, (key, value) => Ext.isString(value)));
#disp {
white-space: pre;
font-family: monospace
}
<script src="https://cdnjs.cloudflare.com/ajax/libs/extjs/4.2.1/builds/ext-core.min.js"></script>
<div id="disp"></div>
My opinionated solution:
function objFilter(obj, filter, nonstrict){
r = {}
if (!filter) return {}
if (typeof filter == 'string') return {[filter]: obj[filter]}
for (p in obj) {
if (typeof filter == 'object' && nonstrict && obj[p] == filter[p]) r[p] = obj[p]
else if (typeof filter == 'object' && !nonstrict && obj[p] === filter[p]) r[p] = obj[p]
else if (typeof filter == 'function'){ if (filter(obj[p],p,obj)) r[p] = obj[p]}
else if (filter.length && filter.includes(p)) r[p] = obj[p]
}
return r
}
Test cases:
obj = {a:1, b:2, c:3}
objFilter(obj, 'a') // returns: {a: 1}
objFilter(obj, ['a','b']) // returns: {a: 1, b: 2}
objFilter(obj, {a:1}) // returns: {a: 1}
objFilter(obj, {'a':'1'}, true) // returns: {a: 1}
objFilter(obj, (v,k,o) => v%2===1) // returns: {a: 1, c: 3}
https://gist.github.com/bernardoadc/872d5a174108823159d845cc5baba337
var foo = {
bar: "Yes",
pipe: "No"
};
const ret = Object.entries(foo).filter(([key, value])=> value === 'Yes');
https://masteringjs.io/tutorials/fundamentals/filter-object
If you have Symbol properties in your object, that should be filtered too, you can not use: Object.keys Object.entries Object.fromEntries, ... because:
Symbol keys are not enumerable !
You could use Reflect.ownKeys and filter keys in reduce
Reflect.ownKeys(o).reduce((a, k) => allow.includes(k) && {...a, [k]: o[k]} || a, {});
(Open DevTools for log output - Symbols are not logged on Stackoverflow UI)
const bKey = Symbol('b_k');
const o = {
a: 1,
[bKey]: 'b',
c: [1, 3],
[Symbol.for('d')]: 'd'
};
const allow = ['a', bKey, Symbol.for('d')];
const z1 = Reflect.ownKeys(o).reduce((a, k) => allow.includes(k) && {...a, [k]: o[k]} || a, {});
console.log(z1); // {a: 1, Symbol(b_k): "b", Symbol(d): "d"}
console.log(bKey in z1) // true
console.log(Symbol.for('d') in z1) // true
This is equal to this
const z2 = Reflect.ownKeys(o).reduce((a, k) => allow.includes(k) && Object.assign(a, {[k]: o[k]}) || a, {});
const z3 = Reflect.ownKeys(o).reduce((a, k) => allow.includes(k) && Object.defineProperty(a, k, {value: o[k]}) || a, {});
console.log(z2); // {a: 1, Symbol(b_k): "b", Symbol(d): "d"}
console.log(z3); // {a: 1, Symbol(b_k): "b", Symbol(d): "d"}
Wrapped in a filter() function, an optional target object could be passed
const filter = (o, allow, t = {}) => Reflect.ownKeys(o).reduce(
(a, k) => allow.includes(k) && {...a, [k]: o[k]} || a,
t
);
console.log(filter(o, allow)); // {a: 1, Symbol(b_k): "b", Symbol(d): "d"}
console.log(filter(o, allow, {e: 'e'})); // {a: 1, e: "e", Symbol(b_k): "b", Symbol(d): "d"}
You could also do something like this where you are filtering on the entries to find the key provided and return the value
let func = function(items){
let val
Object.entries(this.items).map(k => {
if(k[0]===kind){
val = k[1]
}
})
return val
}
If you wish to mutate the same object rather than create a new one.
The following example will delete all 0 or empty values:
const sev = { a: 1, b: 0, c: 3 };
const deleteKeysBy = (obj, predicate) =>
Object.keys(obj)
.forEach( (key) => {
if (predicate(obj[key])) {
delete(obj[key]);
}
});
deleteKeysBy(sev, val => !val);
Like everyone said, do not screw around with prototype. Instead, simply write a function to do so. Here is my version with lodash:
import each from 'lodash/each';
import get from 'lodash/get';
const myFilteredResults = results => {
const filteredResults = [];
each(results, obj => {
// filter by whatever logic you want.
// sample example
const someBoolean = get(obj, 'some_boolean', '');
if (someBoolean) {
filteredResults.push(obj);
}
});
return filteredResults;
};
If you don't need the original object, this is a simple, very boring answer that doesn't waste memory:
const obj = {'a': 'want this', 'b': 'want this too', 'x': 'remove this'}
const keep = new Set(['a', 'b', 'c'])
function filterObject(obj, keep) {
Object.keys(obj).forEach(key => {
if (!keep.has(key)) {
delete obj[key]
}
})
}
If you're only filtering a small number of objects, and your objects don't have many keys, you might not want to bother with constructing a Set, in which case use array.includes instead of set.has.
I just wanted to add the way that I do it because it saves me creating extra functions, I think is cleaner and I didn't see this answer:
let object = {a: 1, b: 2, c: 3};
[object].map(({a,c}) => ({a,c}))[0]; // {a:1, c:2}
The cool thing is that also works on arrays of objects:
let object2 = {a: 4, b: 5, c: 6, d: 7};
[object, object2].map(({a,b,c,d}) => ({a,c})); //[{"a":1,"c":3},{"a":4,"c":6}]
[object, object2].map(({a,d}) => ({a,d})); //[{"a":1,"d":undefined},{"a":4,"d":7}]
In these cases I use the jquery $.map, which can handle objects. As mentioned on other answers, it's not a good practice to change native prototypes (https://developer.mozilla.org/en-US/docs/Web/JavaScript/Inheritance_and_the_prototype_chain#Bad_practice_Extension_of_native_prototypes)
Below is an example of filtering just by checking some property of your object. It returns the own object if your condition is true or returns undefined if not. The undefined property will make that record disappear from your object list;
$.map(yourObject, (el, index)=>{
return el.yourProperty ? el : undefined;
});