push only unique elements in an array - javascript

I have array object(x) that stores json (key,value) objects. I need to make sure that x only takes json object with unique key. Below, example 'id' is the key, so i don't want to store other json objects with 'item1' key.
x = [{"id":"item1","val":"Items"},{"id":"item1","val":"Items"},{"id":"item1","val":"Items"}]
var clickId = // could be "item1", "item2"....
var found = $.inArray(clickId, x); //
if(found >=0)
{
x.splice(found,1);
}
else{
x.push(new Item(clickId, obj)); //push json object
}

would this accomplish what you're looking for? https://jsfiddle.net/gukv9arj/3/
x = [
{"id":"item1","val":"Items"},
{"id":"item1","val":"Items"},
{"id":"item2","val":"Items"}
];
var clickId = [];
var list = JSON.parse(x);
$.each(list, function(index, value){
if(clickId.indexOf(value.id) === -1){
clickId.push(value.id);
}
});

You can't use inArray() because you are searching for an object.
I'd recommend rewriting a custom find using Array.some() as follows.
var x = [{"id":"item1","val":"Items"},{"id":"item1","val":"Items"},{"id":"item1","val":"Items"}]
var clickId = "item1";
var found = x.some(function(value) {
return value.id === clickId;
});
alert(found);

Almost 6 years later i ended up in this question, but i needed to fill a bit more complex array, with objects. So i needed to add something like this.
var values = [
{value: "value1", selected: false},
{value: "value2", selected: false}
//there cannot be another object with value = "value1" within the collection.
]
So I was looking for the value data not to be repeated (in an object's array), rather than just the value in a string's array, as required in this question. This is not the first time i think in doing something like this in some JS code.
So i did the following:
let valueIndex = {};
let values = []
//I had the source data in some other and more complex array.
for (const index in assetsArray)
{
const element = assetsArray[index];
if (!valueIndex[element.value])
{
valueIndex[element.value] = true;
values.push({
value: element.value,
selected: false
});
}
}
I just use another object as an index, so the properties in an object will never be repated. This code is quite easy to read and surely is compatible with any browser. Maybe someone comes with something better. You are welcome to share!
Hopes this helps someone else.

JS objects are great tools to use for tracking unique items. If you start with an empty object, you can incrementally add keys/values. If the object already has a key for a given item, you can set it to some known value that is use used to indicate a non-unique item.
You could then loop over the object and push the unique items to an array.
var itemsObj = {};
var itemsList = [];
x = [{"id":"item1","val":"foo"},
{"id":"item2","val":"bar"},
{"id":"item1","val":"baz"},
{"id":"item1","val":"bez"}];
for (var i = 0; i < x.length; i++) {
var item = x[i];
if (itemsObj[item.id]) {
itemsObj[item.id] = "dupe";
}
else {
itemsObj[item.id] = item;
}
}
for (var myKey in itemsObj) {
if (itemsObj[myKey] !== "dupe") {
itemsList.push(itemsObj[myKey]);
}
}
console.log(itemsList);
See a working example here: https://jsbin.com/qucuso
If you want a list of items that contain only the first instance of an id, you can do this:
var itemsObj = {};
var itemsList = [];
x = [{"id":"item1","val":"foo"},
{"id":"item2","val":"bar"},
{"id":"item1","val":"baz"},
{"id":"item1","val":"bez"}];
for (var i = 0; i < x.length; i++) {
var item = x[i];
if (!itemsObj[item.id]) {
itemsObj[item.id] = item;
itemsList.push(item);
}
}
console.log(itemsList);

This is late but I did something like the following:
let MyArray = [];
MyArray._PushAndRejectDuplicate = function(el) {
if (this.indexOf(el) == -1) this.push(el)
else return;
}
MyArray._PushAndRejectDuplicate(1); // [1]
MyArray._PushAndRejectDuplicate(2); // [1,2]
MyArray._PushAndRejectDuplicate(1); // [1,2]

This is how I would do it in pure javascript.
var x = [{"id":"item1","val":"Items"},{"id":"item1","val":"Items"},{"id":"item1","val":"Items"}];
function unique(arr, comparator) {
var uniqueArr = [];
for (var i in arr) {
var found = false;
for (var j in uniqueArr) {
if (comparator instanceof Function) {
if (comparator.call(null, arr[i], uniqueArr[j])) {
found = true;
break;
}
} else {
if (arr[i] == uniqueArr[j]) {
found = true;
break;
}
}
}
if (!found) {
uniqueArr.push(arr[i]);
}
}
return uniqueArr;
};
u = unique(x, function(a,b){ return a.id == b.id; });
console.log(u);
y = [ 1,1,2,3,4,5,5,6,1];
console.log(unique(y));

Create a very readable solution with lodash.
x = _.unionBy(x, [new Item(clickId, obj)], 'id');

let x = [{id:item1,data:value},{id:item2,data:value},{id:item3,data:value}]
let newEle = {id:newItem,data:value}
let prev = x.filter(ele=>{if(ele.id!=new.id)return ele);
newArr = [...prev,newEle]

Related

Javascript remove duplicated object from array

i'm having trouble to remove duplicated object from my array
example:
var list = [{place:"AAA",name:"Me"}, {place:"BBB",name:"You"}, {place:"AAA",name:"Him"}];
in this example i have 3 objects, and i want to remove the object that have the duplicated place
Just in case someone wonders: underscore.js solution:
var list = [{place:"AAA",name:"Me"}, {place:"BBB",name:"You"}, {place:"AAA",name:"Him"}];
_.uniq(list, function(item, key, a) {
return item.place;
})
Example Fiddle
A simple one:
var list = [{place:"AAA",name:"Me"}, {place:"BBB",name:"You"}, {place:"AAA",name:"Him"}];
list.forEach(function(i) {
var duplicates = list.filter(function(j) {
return j !== i && j.place == i.place;
});
duplicates.forEach(function(d) { list.splice(list.indexOf(d), 1); });
});
// list = [{place:"AAA",name:"Me"}, {place:"BBB",name:"You"}];
document.write(JSON.stringify(list));
As you added:
i want to remove just one, dont matter wich one
If you want to remove duplicated items and keep only the first occcurence of particular place, you can simply use a simple loop to re-create a new array from the input:
var list = [{place:"AAA",name:"Me"}, {place:"BBB",name:"You"}, {place:"AAA",name:"Him"}];
var uniqPlace = function(array){
var result = [];
array.forEach(function(el){
if (result.filter(function(n){ return n.place === el.place }).length==0){
result.push(el);
}
})
return result;
}
Output:
uniqPlace(list);
[{"place":"AAA","name":"Me"},{"place":"BBB","name":"You"}]
Try this.
var result = {};
for (i = 0, n = arr.length; i < n; i++) {
var item = arr[i];
result[ item.place + " - " + item.name ] = item;
}
Loop the result again, and recreate the array.
i = 0;
for(var item in result) {
clearnArr[i++] = result[item];
}
Create a object to store the items by their place value, as the new item with the same key will overwrite the old one, this will easily remove all dulplicates.
var list = [{place:"AAA",name:"Me"}, {place:"BBB",name:"You"}, {place:"AAA",name:"Him"}];
var removeDuplicate = function(list) {
var keyStore = {};
var output = [];
// If you want to creata totally new one from old, use
// list = JSON.parse(JSON.stringify(list));
// The above commented out code will create a copy of list, so the items in output will not affect the original ones.
list.forEach(function(item) {
// new one overwrites old one.
keyStore[item.place] = item;
});
var key;
for (key in keyStore) {
output.push(keyStore[key]);
}
return output;
};
console.log(removeDuplicate(list));
3 way to remove duplicate objects from array
let list = [{place:"AAA",name:"Me"},
{place:"BBB",name:"You"},
{place:"AAA",name:"Him"}];
let output1 = Array.from(new Set(list.map(list=>list.place))).map(place=>{
return {
place: place,
name: list.find(a=>a.place===place).name
}
})
console.log('------------------------1st way')
console.log(output1)
let output2 = list.reduce((accumulator, element) => {
if (!accumulator.find(el => el['place'] === element['place'])) {
accumulator.push(element);
}
return accumulator;
},[]);
console.log('------------------------2nd way')
console.log(output2)
const output3 = [];
const map = new Map();
for (const object of list) {
if(!map.has(object.place)){
map.set(object.place, true);
output3.push({
place: object.place,
name: object.name
});
}
}
console.log('------------------------3rd way')
console.log(output3)

Nest JSON from array

I am trying to achieve something which seemed very basic but is getting me mad over the last days.
I have a simple array : ["a","b","c","d","e"] and I want to turn it into a nested JSON like this:
{"a":{"b":{"c":{"d":{"e":""}}}}}
Looping over it, I ran in problems like "how do you save the last key to set it afterwards without erasing it" and so on.
Does anyone has an idea?
You might have had problems because you were looping in the wrong direction. Try to build the object from inside-out:
array.reduceRight(function(v, key) {
var o = {};
o[key] = v;
return o;
}, "")
or, with a loop:
var val = "";
for (var i=array.length; i--; )
var o = {};
o[array[i]] = val;
val = o;
}
return val;
Here's one way to do it, recursively:
function convertToNestedObject(arr) {
var result = {};
if (arr.length === 1) {
result[arr[0]] = '';
} else {
result[arr[0]] = convertToNestedObject(arr.slice(1, arr.length));
}
return result;
}
You could pass the start index in to the function instead of using slice and creating copies of the array:
function convertToNestedObject(arr, startIndex) {
var result = {};
if (arr.length - startIndex === 1) {
result[arr[startIndex]] = '';
} else {
result[arr[startIndex]] = convertToNestedObject(arr, startIndex + 1);
}
return result;
}
Example: http://jsfiddle.net/jwcxfaeb/1/
Put current element as key and empty object ({}) as value. Continue with newly inserted empty object.
function toNested(arr){
var nested = {};
var temp = nested;
for(var i=0; i<arr.length; i++){
temp[arr[i]] = {};
temp = temp[arr[i]];
}
return nested;
}

Easy way to set javascript object multilevel property?

I am trying to create a javascript object like
var allUserExpiry={};
allUserExpiry[aData.userId][aData.courseId][aData.uscId] = aData;
But I am getting an error like allUserExpiry[aData.userId] undefined.
Is there a way, whereby I can set multi-level JS-Object keys? or is it important that I should go by doing allUserExpiry[aData.userId]={}, then allUserExpiry[aData.userId][aData.courseId]={} ?
Please let me know if there are any utility functions available for the same.
No, there is no way to set "multilevel keys". You need to initialize each object before trying to add properties to it.
var allUserExpiry = {};
allUserExpiry[aData.userId] = {}
allUserExpiry[aData.userId][aData.courseId] = {}
allUserExpiry[aData.userId][aData.courseId][aData.uscId] = aData;
Using Computed property names from ES6, it is possible to do:
var allUserExpiry = {
[aData.userId] = {
[aData.courseId]: {
[aData.uscId]: aData
}
}
};
https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Operators/Object_initializer#Computed_property_names
Simply use loadash,
let object = {};
let property = "a.b.c";
let value = 1;
_.set(object, property, value); // sets property based on path
let value = _.get(object, property, default); // gets property based on path
Or you can do it:
function setByPath(obj, path, value) {
var parts = path.split('.');
var o = obj;
if (parts.length > 1) {
for (var i = 0; i < parts.length - 1; i++) {
if (!o[parts[i]])
o[parts[i]] = {};
o = o[parts[i]];
}
}
o[parts[parts.length - 1]] = value;
}
And use:
setByPath(obj, 'path.path2.path', someValue);
This approach has many weak places, but for fun... :)
Why not just do this?
var allUserExpiry={};
allUserExpiry[aData.userId] = {aData.courseId: {aData.uscId: aData}};
I have a pretty hacky but short way of doing it in IE9+ as well as real browsers.
Given var path = 'aaa.bbb.ccc.ddd.eee'; where path is what your intending to make into an object and var result = {}; will will create the object {aaa: {bbb: {ccc: {ddd: {eee: {}}}}}
result = {}
path.split('.').reduce(function(prev, e) {
var newObj = {};
prev[e] = newObj;
return newObj;
}, result);
will store the object in result.
How it works:
split('.') converts the input into ['aaa', 'bbb', 'ccc', 'ddd', 'eee']
reduce(function (...) {...}, result) runs through the array created by split, and for each entry will pass along a returned value to the next one. In our case we pass the new object through after adding the new object to the old one. This creates a chain of objects. reduce returns the last object you return inside of it, so we have to defined result beforehand.
This relies on using references so it won't be immediately clear how it works if you're expecting your code to be maintained by anyone else and should probably be avoided to be honest, but it works at least.
You can also use the following to create the initial structure:
var x = function(obj, keys) {
if (!obj) return;
var i, t;
for (i = 0; i < keys.length; i++) {
if (!t) {
t = obj[keys[i]] = {};
} else {
t[keys[i]] = {};
t = t[keys[i]];
}
}
};
var a = {};
x(a, ['A', 'B', 'C', 'D', 'E', 'F']);
Another approach without strings or array as argument.
function fillObject() {
var o = arguments[0];
for(var i = 1; i < arguments.length-1; i++) {
if(!o.hasOwnProperty(arguments[i])) {
o[arguments[i]] = {};
}
if(i < arguments.length-2) {
o = o[arguments[i]];
}else {
o[arguments[i]] = arguments[i+1]
}
}
}
var myObj = {"foo":{}};
fillObject(myObj,"back","to","the","future",2);
console.log(JSON.stringify(myObj));
// {"foo":{},"back":{"to":{"the":{"future":2}}}}
But I wouldn't use it :-) It's just for fun.
Because I don't like too much intelligent algorithm. (If it was in this category)
Using lodash you can do this easily (node exists and empty check for that node)..
var lodash = require('lodash-contrib');
function invalidateRequest(obj, param) {
var valid = true;
param.forEach(function(val) {
if(!lodash.hasPath(obj, val)) {
valid = false;
} else {
if(lodash.getPath(obj, val) == null || lodash.getPath(obj, val) == undefined || lodash.getPath(obj, val) == '') {
valid = false;
}
}
});
return valid;
}
Usage:
leaveDetails = {
"startDay": 1414998000000,
"endDay": 1415084400000,
"test": { "test1" : 1234 }
};
var validate;
validate = invalidateRequest(leaveDetails, ['startDay', 'endDay', 'test.test1']);
it will return boolean.
Another solution using reduce function (thanks Brian K).
Here we created a get/set to general proposes. The first function return the value in any level. The key is splited considering the separator. the function return the value refered from last index in the key's array
The second function will set the new value considering the last index of the splited key
the code:
function getObjectMultiLevelValue(_array,key,separator){
key = key.split(separator || '.');
var _value = JSON.parse(JSON.stringify(_array));
for(var ki in key){
_value = _value[key[ki]];
}
return _value;
}
function setObjectMultiLevelValue(_array,key,value,forcemode,separator){
key.split(separator || '.').reduce(function(prev, currKey, currIndex,keysArr) {
var newObj = {};
if(prev[currKey] && !forcemode){
newObj = prev[currKey];
}
if(keysArr[keysArr.length-1] == currKey){
newObj = value;
prev[currKey] = newObj;
}
prev[currKey] = newObj;
return newObj;
}, _array);
return _array;
}
//testing the function
//creating an array
var _someArray = {a:'a',b:'b',c:{c1:'c1',c2:{c21:'nothing here...'}}};
//a multilevel key to test
var _key = 'a,a1,a21';
//any value
var _value = 'new foo in a21 key forcing replace old path';
//here the new value will be inserted even if the path exists (forcemode=true). Using comma separator
setObjectMultiLevelValue(_someArray,_key,_value,true,',');
console.log('_someArray:');
console.log(JSON.stringify(_someArray));
//inserting another value in another key... using default separator
_key = 'c.c2.c21';
_value = 'new foo in c21 key';
setObjectMultiLevelValue(_someArray,_key,_value);
console.log('_someArray:');
console.log(JSON.stringify(_someArray));
//recovering the saved value with different separators
_key = 'a,a1,a21';
console.log(getObjectMultiLevelValue(_someArray,_key,','));
_key = 'c.c2.c21';
console.log(getObjectMultiLevelValue(_someArray,_key));
Let assume our object is
const data = {
//some other data
userInfo: {},
};
First, define a new property of that object
data.userInfo.vehicle = {};
then simply
data.userInfo.vehicle.vehicleType = state.userInfo.vehicleType;

Create child objects from parent with same property values [duplicate]

This question already has answers here:
How to put items into grouped arrays where grouped by a particular key
(3 answers)
Closed 9 years ago.
I have a parent object. I want to create child objects from the parent with the same key value pair.
e.g.
parentJSON = {[name:"a1",address:"b1",comp:"c1"],
[name:"a2",address:"b2",comp:"c1"],
[name:"a3",address:"b3",comp:"c2"],
[name:"a4",address:"b4",comp:"c2"],
[name:"a5",address:"b5",comp:"c2"],
[name:"a6",address:"b6",comp:"c3"]}
Now I want to create child objects having same "comp" value.
e.g.
childJSON1 = {[name:"a1",address:"b1",comp:"c1"],
[name:"a2",address:"b2",comp:"c1"]}
childJSON2 = {[name:"a3",address:"b3",comp:"c2"],
[name:"a4",address:"b4",comp:"c2"],
[name:"a5",address:"b5",comp:"c2"]}
childJSON3 = {[name:"a6",address:"b6",comp:"c3"]}
This is what I tried to make it little bit (it will change the parent object with a key indicating number of repetition):
parentJSON = [1,2,3,3,4,4,4,5];
var i=0, x, count, item;
while(i < parentJSON.length) {
count = 1;
item = parentJSON[i];
x = i+1;
while(x < parentJSON.length &&
(x = parentJSON.indexOf(item, x)) != -1) {
count += 1;
parentJSON.splice(x,1);
}
parentJSON[i] = new Array(parentJSON[i],count);
++i;
}
console.log(parentJSON);`
first of all your json is in the incorrect format, it should look like this
[{name:"a1",address:"b1",comp:"c1"},
{name:"a2",address:"b2",comp:"c1"},
{name:"a3",address:"b3",comp:"c2"},
{name:"a4",address:"b4",comp:"c2"},
{name:"a5",address:"b5",comp:"c2"},
{name:"a6",address:"b6",comp:"c3"}]
An array of objects.
My attempt, also very readable.
var result = {};
$.each(parentJSON, function (i, item) {
if(!result[item.comp]) {
result[item.comp] = [];
}
(result[item.comp]).push(item);
});
alert(JSON.stringify(result))
JsFiddle
First of all your json is actually invalid. You may have an array of objects, but not object which contains an array like that. Also your arrays looks more like objects, because the syntax with the dots is used for objects. Here is how I guess should look like:
var parentJSON = [
[{name:"a1",address:"b1",comp:"c1"}],
[{name:"a2",address:"b2",comp:"c1"}],
[{name:"a3",address:"b3",comp:"c2"}],
[{name:"a4",address:"b4",comp:"c2"}],
[{name:"a5",address:"b5",comp:"c2"}],
[{name:"a6",address:"b6",comp:"c3"}]
];
var child1 = parentJSON.slice(0, 2);
var child2 = parentJSON.slice(2, 5);
And you may use the .slice method to get specific elements of the array.
So..you need to clone objects?
maybe tou can try sth like this:
var sergi= {
name: "sergi",
age: 33
};
var bill = (JSON.parse(JSON.stringify(sergi)));
bill.name = "Bill";
console.log(sergi);
console.log(bill);
parentJSON = function(){
return [
{name:"a1",address:"b1",comp:"c1"},
{name:"a2",address:"b2",comp:"c1"},
{name:"a3",address:"b3",comp:"c2"},
{name:"a4",address:"b4",comp:"c2"},
{name:"a5",address:"b5",comp:"c2"},
{name:"a6",address:"b6",comp:"c3"}
];
}
childJSON1 = new parentJSON().slice(0,2);
childJSON2 = new parentJSON().slice(2,5);
childJSON3 = new parentJSON().slice(5,6);
Try this:
DEMO
var data = [
[{name:"a1",address:"b1",comp:"c1"}],
[{name:"a2",address:"b2",comp:"c1"}],
[{name:"a3",address:"b3",comp:"c2"}],
[{name:"a4",address:"b4",comp:"c2"}],
[{name:"a5",address:"b5",comp:"c2"}],
[{name:"a6",address:"b6",comp:"c3"}]
];
var groups = {};
$.each(data, function(i, item) {
var comp = item.comp;
delete item.comp;
if(groups[comp]) {
groups[comp].push(item);
} else {
groups[comp] = [item];
}
});
var result = $.map(data, function(group, key) {
var obj = {};
obj[key] = group;
return obj;
});
alert(JSON.stringify(groups))

Get the index of the object inside an array, matching a condition

I have an array like this:
[{prop1:"abc",prop2:"qwe"},{prop1:"bnmb",prop2:"yutu"},{prop1:"zxvz",prop2:"qwrq"},...]
How can I get the index of the object that matches a condition, without iterating over the entire array?
For instance, given prop2=="yutu", I want to get index 1.
I saw .indexOf() but think it's used for simple arrays like ["a1","a2",...]. I also checked $.grep() but this returns objects, not the index.
As of 2016, you're supposed to use Array.findIndex (an ES2015/ES6 standard) for this:
a = [
{prop1:"abc",prop2:"qwe"},
{prop1:"bnmb",prop2:"yutu"},
{prop1:"zxvz",prop2:"qwrq"}];
index = a.findIndex(x => x.prop2 ==="yutu");
console.log(index);
It's supported in Google Chrome, Firefox and Edge. For Internet Explorer, there's a polyfill on the linked page.
Performance note
Function calls are expensive, therefore with really big arrays a simple loop will perform much better than findIndex:
let test = [];
for (let i = 0; i < 1e6; i++)
test.push({prop: i});
let search = test.length - 1;
let count = 100;
console.time('findIndex/predefined function');
let fn = obj => obj.prop === search;
for (let i = 0; i < count; i++)
test.findIndex(fn);
console.timeEnd('findIndex/predefined function');
console.time('findIndex/dynamic function');
for (let i = 0; i < count; i++)
test.findIndex(obj => obj.prop === search);
console.timeEnd('findIndex/dynamic function');
console.time('loop');
for (let i = 0; i < count; i++) {
for (let index = 0; index < test.length; index++) {
if (test[index].prop === search) {
break;
}
}
}
console.timeEnd('loop');
As with most optimizations, this should be applied with care and only when actually needed.
How can I get the index of the object tha match a condition (without iterate along the array)?
You cannot, something has to iterate through the array (at least once).
If the condition changes a lot, then you'll have to loop through and look at the objects therein to see if they match the condition. However, on a system with ES5 features (or if you install a shim), that iteration can be done fairly concisely:
var index;
yourArray.some(function(entry, i) {
if (entry.prop2 == "yutu") {
index = i;
return true;
}
});
That uses the new(ish) Array#some function, which loops through the entries in the array until the function you give it returns true. The function I've given it saves the index of the matching entry, then returns true to stop the iteration.
Or of course, just use a for loop. Your various iteration options are covered in this other answer.
But if you're always going to be using the same property for this lookup, and if the property values are unique, you can loop just once and create an object to map them:
var prop2map = {};
yourArray.forEach(function(entry) {
prop2map[entry.prop2] = entry;
});
(Or, again, you could use a for loop or any of your other options.)
Then if you need to find the entry with prop2 = "yutu", you can do this:
var entry = prop2map["yutu"];
I call this "cross-indexing" the array. Naturally, if you remove or add entries (or change their prop2 values), you need to update your mapping object as well.
What TJ Crowder said, everyway will have some kind of hidden iteration, with lodash this becomes:
var index = _.findIndex(array, {prop2: 'yutu'})
var CarId = 23;
//x.VehicleId property to match in the object array
var carIndex = CarsList.map(function (x) { return x.VehicleId; }).indexOf(CarId);
And for basic array numbers you can also do this:
var numberList = [100,200,300,400,500];
var index = numberList.indexOf(200); // 1
You will get -1 if it cannot find a value in the array.
var index;
yourArray.some(function (elem, i) {
return elem.prop2 === 'yutu' ? (index = i, true) : false;
});
Iterate over all elements of array.
It returns either the index and true or false if the condition does not match.
Important is the explicit return value of true (or a value which boolean result is true). The single assignment is not sufficient, because of a possible index with 0 (Boolean(0) === false), which would not result an error but disables the break of the iteration.
Edit
An even shorter version of the above:
yourArray.some(function (elem, i) {
return elem.prop2 === 'yutu' && ~(index = i);
});
Using Array.map() and Array.indexOf(string)
const arr = [{
prop1: "abc",
prop2: "qwe"
}, {
prop1: "bnmb",
prop2: "yutu"
}, {
prop1: "zxvz",
prop2: "qwrq"
}]
const index = arr.map(i => i.prop2).indexOf("yutu");
console.log(index);
The best & fastest way to do this is:
const products = [
{ prop1: 'telephone', prop2: 996 },
{ prop1: 'computadora', prop2: 1999 },
{ prop1: 'bicicleta', prop2: 995 },
];
const index = products.findIndex(el => el.prop2 > 1000);
console.log(index); // 1
I have seen many solutions in the above.
Here I am using map function to find the index of the search text in an array object.
I am going to explain my answer with using students data.
step 1: create array object for the students(optional you can create your own array object).
var students = [{name:"Rambabu",htno:"1245"},{name:"Divya",htno:"1246"},{name:"poojitha",htno:"1247"},{name:"magitha",htno:"1248"}];
step 2: Create variable to search text
var studentNameToSearch = "Divya";
step 3: Create variable to store matched index(here we use map function to iterate).
var matchedIndex = students.map(function (obj) { return obj.name; }).indexOf(studentNameToSearch);
var students = [{name:"Rambabu",htno:"1245"},{name:"Divya",htno:"1246"},{name:"poojitha",htno:"1247"},{name:"magitha",htno:"1248"}];
var studentNameToSearch = "Divya";
var matchedIndex = students.map(function (obj) { return obj.name; }).indexOf(studentNameToSearch);
console.log(matchedIndex);
alert("Your search name index in array is:"+matchedIndex)
You can use the Array.prototype.some() in the following way (as mentioned in the other answers):
https://jsfiddle.net/h1d69exj/2/
function findIndexInData(data, property, value) {
var result = -1;
data.some(function (item, i) {
if (item[property] === value) {
result = i;
return true;
}
});
return result;
}
var data = [{prop1:"abc",prop2:"qwe"},{prop1:"bnmb",prop2:"yutu"},{prop1:"zxvz",prop2:"qwrq"}]
alert(findIndexInData(data, 'prop2', "yutu")); // shows index of 1
function findIndexByKeyValue(_array, key, value) {
for (var i = 0; i < _array.length; i++) {
if (_array[i][key] == value) {
return i;
}
}
return -1;
}
var a = [
{prop1:"abc",prop2:"qwe"},
{prop1:"bnmb",prop2:"yutu"},
{prop1:"zxvz",prop2:"qwrq"}];
var index = findIndexByKeyValue(a, 'prop2', 'yutu');
console.log(index);
Try this code
var x = [{prop1:"abc",prop2:"qwe"},{prop1:"bnmb",prop2:"yutu"},{prop1:"zxvz",prop2:"qwrq"}]
let index = x.findIndex(x => x.prop1 === 'zxvz')
Another easy way is :
function getIndex(items) {
for (const [index, item] of items.entries()) {
if (item.prop2 === 'yutu') {
return index;
}
}
}
const myIndex = getIndex(myArray);
Georg have already mentioned ES6 have Array.findIndex for this.
And some other answers are workaround for ES5 using Array.some method.
One more elegant approach can be
var index;
for(index = yourArray.length; index-- > 0 && yourArray[index].prop2 !== "yutu";);
At the same time I will like to emphasize, Array.some may be implemented with binary or other efficient searching technique. So, it might perform better over for loop in some browser.
Why do you not want to iterate exactly ? The new Array.prototype.forEach are great for this purpose!
You can use a Binary Search Tree to find via a single method call if you want. This is a neat implementation of BTree and Red black Search tree in JS - https://github.com/vadimg/js_bintrees - but I'm not sure whether you can find the index at the same time.
One step using Array.reduce() - no jQuery
var items = [{id: 331}, {id: 220}, {id: 872}];
var searchIndexForId = 220;
var index = items.reduce(function(searchIndex, item, index){
if(item.id === searchIndexForId) {
console.log('found!');
searchIndex = index;
}
return searchIndex;
}, null);
will return null if index was not found.
var list = [
{prop1:"abc",prop2:"qwe"},
{prop1:"bnmb",prop2:"yutu"},
{prop1:"zxvz",prop2:"qwrq"}
];
var findProp = p => {
var index = -1;
$.each(list, (i, o) => {
if(o.prop2 == p) {
index = i;
return false; // break
}
});
return index; // -1 == not found, else == index
}

Categories