Find a value in an array of objects in Javascript

问题:

This question already has an answer here:

• Get JavaScript object from array of objects by value of property [duplicate] 17 answers

I know similar questions have been asked before, but this one is a little different. I have an array of unnamed objects, which contain an array of named objects, and I need to get the object where \"name\" is \"string 1\". Here is an example array.

var array = [
    { name:\"string 1\", value:\"this\", other: \"that\" },
    { name:\"string 2\", value:\"this\", other: \"that\" }
];

Update: I should have said this earlier, but once I find it, I want to replace it with an edited object.

回答1:

You can loop over the array and test for that property:

function search(nameKey, myArray){
    for (var i=0; i < myArray.length; i++) {
        if (myArray[i].name === nameKey) {
            return myArray[i];
        }
    }
}

var array = [
    { name:\"string 1\", value:\"this\", other: \"that\" },
    { name:\"string 2\", value:\"this\", other: \"that\" }
];

var resultObject = search(\"string 1\", array);

回答2:

Finding the array element:

let arr = [
    { name:\"string 1\", value:\"this\", other: \"that\" },
    { name:\"string 2\", value:\"this\", other: \"that\" }
];

let obj = arr.find(o => o.name === \'string 1\');

console.log(obj);

---

Replacing the array element:

let arr = [
    { name:\"string 1\", value:\"this\", other: \"that\" },
    { name:\"string 2\", value:\"this\", other: \"that\" }
];

let obj = arr.find((o, i) => {
    if (o.name === \'string 1\') {
        arr[i] = { name: \'new string\', value: \'this\', other: \'that\' };
        return true; // stop searching
    }
});

console.log(arr);

回答3:

In ES6 you can use Array.prototype.find(predicate, thisArg?) like so:

array.find(x => x.name === \'string 1\')

http://exploringjs.com/es6/ch_arrays.html#_searching-for-array-elements https://developer.mozilla.org/en/docs/Web/JavaScript/Reference/Global_Objects/Array/find

To then replace said object (and use another cool ES6 method fill) you could do something like:

let obj = array.find(x => x.name === \'string 1\');
let index = array.indexOf(obj);
array.fill(obj.name=\'some new string\', index, index++);

回答4:

As per ECMAScript 6, you can use the findIndex function.

array[array.findIndex(x => x.name == \'string 1\')]

回答5:

with underscore.js use the findWhere method:

var array = [
    { name:\"string 1\", value:\"this\", other: \"that\" },
    { name:\"string 2\", value:\"this\", other: \"that\" }
];


var result = _.findWhere(array, {name: \'string 1\'});

console.log(result.name);

See this in JSFIDDLE

回答6:

Either use a simple for-loop:

var result = null;
for (var i = 0; i < array.length; i++) { 
  if (array[i].name === \"string 1\") { 
    result = array[i];
    break;
  } 
}

Or if you can, that is, if your browser supports it, use Array.filter, which is much more terse:

var result = array.filter(function (obj) {
  return obj.name === \"string 1\";
})[0];

回答7:

New answer

I added the prop as a parameter, to make it more general and reusable

/**
 * Represents a search trough an array.
 * @function search
 * @param {Array} array - The array you wanna search trough
 * @param {string} key - The key to search for
 * @param {string} [prop] - The property name to find it in
 */

function search(array, key, prop){
    // Optional, but fallback to key[\'name\'] if not selected
    prop = (typeof prop === \'undefined\') ? \'name\' : prop;    

    for (var i=0; i < array.length; i++) {
        if (array[i][prop] === key) {
            return array[i];
        }
    }
}

Usage:

var array = [
    { 
        name:\'string 1\', 
        value:\'this\', 
        other: \'that\' 
    },
    { 
        name:\'string 2\', 
        value:\'this\', 
        other: \'that\' 
    }
];

search(array, \'string 1\');
// or for other cases where the prop isn\'t \'name\'
// ex: prop name id
search(array, \'string 1\', \'id\');

Mocha test:

var assert = require(\'chai\').assert;

describe(\'Search\', function() {
    var testArray = [
        { 
            name: \'string 1\', 
            value: \'this\', 
            other: \'that\' 
        },
        { 
            name: \'string 2\', 
            value: \'new\', 
            other: \'that\' 
        }
    ];

    it(\'should return the object that match the search\', function () {
        var name1 = search(testArray, \'string 1\');
        var name2 = search(testArray, \'string 2\');

        assert.equal(name1, testArray[0]);
        assert.equal(name2, testArray[1]);

        var value1 = search(testArray, \'this\', \'value\');
        var value2 = search(testArray, \'new\', \'value\');

        assert.equal(value1, testArray[0]);
        assert.equal(value2, testArray[1]);
    });

    it(\'should return undefined becuase non of the objects in the array have that value\', function () {
        var findNonExistingObj = search(testArray, \'string 3\');

        assert.equal(findNonExistingObj, undefined);
    });

    it(\'should return undefined becuase our array of objects dont have ids\', function () {
        var findById = search(testArray, \'string 1\', \'id\');

        assert.equal(findById, undefined);
    });
});

test results:

Search
    ✓ should return the object that match the search
    ✓ should return undefined becuase non of the objects in the array have that value
    ✓ should return undefined becuase our array of objects dont have ids


  3 passing (12ms)

Old answer - removed due to bad practices

if you wanna know more why it\'s bad practice then see this article:

Why is extending native objects a bad practice?

Prototype version of doing an array search:

Array.prototype.search = function(key, prop){
    for (var i=0; i < this.length; i++) {
        if (this[i][prop] === key) {
            return this[i];
        }
    }
}

Usage:

var array = [
    { name:\'string 1\', value:\'this\', other: \'that\' },
    { name:\'string 2\', value:\'this\', other: \'that\' }
];

array.search(\'string 1\', \'name\');

回答8:

var array = [
    { name:\"string 1\", value:\"this\", other: \"that\" },
    { name:\"string 2\", value:\"this\", other: \"that\" }
];

var foundValue = array.filter(obj=>obj.name===\'string 1\');

console.log(foundValue);

回答9:

One line answer. You can use filter function to get result.

var array = [
    { name:\"string 1\", value:\"this\", other: \"that\" },
    { name:\"string 2\", value:\"this\", other: \"that\" }
];

console.log(array.filter(function(arr){return arr.name == \'string 1\'})[0]);

回答10:

Considering you have following snippet:

var array = [
    { name:\"string 1\", value:\"this\", other: \"that\" },
    { name:\"string 2\", value:\"this\", other: \"that\" }
];

You can use the following function to search for items

const search = what => array.find(element => element.name === what);

And you can check whether the item was found or not.

if (search(\"string 1\")) {
    console.log(search.value, search.other);
} else {
    console.log(\'No result found\');
}

回答11:

With a foreach:

let itemYouWant = null;
array.forEach((item) => {
    if (item.name === \'string 1\') {
        itemYouWant = item;
    }
});
console.log(itemYouWant);

回答12:

You can do it with a simple loop:

var obj = null;    
for (var i = 0; i < array.length; i++) {
    if (array[i].name == \"string 1\") {
        obj = array[i];
        break;
    }
}

回答13:

Another way (to aid @NullUserException and @Wexoni\'s comments) is to retrieve the object\'s index in the array and then go from there:

var index = array.map(function(obj){ return obj.name; }).indexOf(\'name-I-am-looking-for\');
// Then we can access it to do whatever we want
array[index] = {name: \'newName\', value: \'that\', other: \'rocks\'};

回答14:

Similar to previous answers I used the following:

    Array.prototype.getIemtByParam = function(paramPair) {
      var key = Object.keys(paramPair)[0];
      return this.find(function(item){return ((item[key] == paramPair[key]) ? true: false)});
    }

usage:

myArray.getIemtByParam(
    {name: \'Sasha\'}
);

回答15:

if you are using jQuery try $.grep().

http://api.jquery.com/jquery.grep/

回答16:

Are you looking for generic Search(Filter) across the item in the object list without specifying the item key

Input

var productList = [{category: \'Sporting Goods\', price: \'$49.99\', stocked: true, name: \'Football\'}, {category: \'Sporting Goods\', price: \'$9.99\', stocked: true, name: \'Baseball\'}, {category: \'Sporting Goods\', price: \'$29.99\', stocked: false, name: \'Basketball\'}, {category: \'Electronics\', price: \'$99.99\', stocked: true, name: \'iPod Touch\'}, {category: \'Electronics\', price: \'$399.99\', stocked: false, name: \'iPhone 5\'}, {category: \'Electronics\', price: \'$199.99\', stocked: true, name: \'Nexus 7\'}]
function customFilter(objList, text){
if(undefined === text || text === \'\' ) return objList;
return objList.filter(product => {
    let flag;
    for(let prop in product){
        flag = false;
        flag = product[prop].toString().indexOf(text) > -1;
        if(flag)
        break;
    }
return flag;
});}

Execute

customFilter(productList, \'$9\');

回答17:

Here is the solution for search and replace

function searchAndUpdate(name,replace){
    var obj = array.filter(function ( obj ) {
        return obj.name === name;
    })[0];
    obj.name = replace;
}

searchAndUpdate(\"string 2\",\"New String 2\");

回答18:

function getValue(){
    for(var i = 0 ; i< array.length; i++){
        var obj = array[i];
        var arr = array[\"types\"];
        for(var j = 0; j<arr.length;j++ ){
            if(arr[j] == \"value\"){
                return obj;
            }
        }

    }
}

回答19:

You can use query-objects from npm. You can search an array of objects using filters.

const queryable = require(\'query-objects\');

const users = [
    {
      firstName: \'George\',
      lastName: \'Eracleous\',
      age: 28
    },
    {
      firstName: \'Erica\',
      lastName: \'Archer\',
      age: 50
    },
    {
      firstName: \'Leo\',
      lastName: \'Andrews\',
      age: 20
    }
];

const filters = [
    {
      field: \'age\',
      value: 30,
      operator: \'lt\'
    },
    {
      field: \'firstName\',
      value: \'Erica\',
      operator: \'equals\'
    }
];

// Filter all users that are less than 30 years old AND their first name is Erica
const res = queryable(users).and(filters);

// Filter all users that are less than 30 years old OR their first name is Erica
const res = queryable(users).or(filters);

回答20:

This answer is good for typescript / Angular 2, 4, 5+

I got this answer with the help of @rujmah answer above. His answer brings in the array count... and then find\'s the value and replaces it with another value...

What this answer does is simply grabs the array name that might be set in another variable via another module / component... in this case the array I build had a css name of stay-dates. So what this does is extract that name and then allows me to set it to another variable and use it like so. In my case it was an html css class.

let obj = this.highlightDays.find(x => x.css); let index = this.highlightDays.indexOf(obj); console.log(\'here we see what hightlightdays is \', obj.css); let dayCss = obj.css;