在Javascript中查找对象数组中的值

Question

我之前已经问过类似的问题,但这个问题有点不同.我有一个未命名的对象数组,其中包含一个命名对象数组,我需要获取"name"为"string 1"的对象.这是一个示例数组.

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

更新:我应该早些说过,但是一旦找到它,我想用一个编辑过的对象替换它.

Answer 1

查找数组元素:

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);

替换数组元素:

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);

Answer 2

您可以遍历数组并测试该属性:

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);

Answer 3

在ES6中你可以Array.prototype.find(predicate, thisArg?)像这样使用:

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

然后替换所述对象(并使用另一个很酷的ES6方法fill),您可以执行以下操作:

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

Answer 4

根据ECMAScript 6,您可以使用该findIndex功能.

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

Answer 5

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);

Answer 6

与underscore.js使用findWhere方法:

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);

在JSFIDDLE中看到这一点

Answer 7

要么使用简单的for循环:

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

或者,如果可以,也就是说,如果您的浏览器支持它,请使用Array.filter,这更简洁:

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

Answer 8

考虑到您有以下代码段:

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

您可以使用以下功能搜索项目

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

您可以检查是否找到了该项目.

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

Answer 9

一行答案.您可以使用过滤功能来获得结果.

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]);

Answer 10

随着foreach:

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

Answer 11

新答案

我添加了prop作为参数,使其更通用和可重用

/**
 * 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];
        }
    }
}

用法:

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');

摩卡测试:

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);
    });
});

检测结果:

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)

旧答案 - 由于不良做法而被删除

如果你想知道为什么这是不好的做法,那么看看这篇文章:

为什么扩展本机对象是一种不好的做法？

进行数组搜索的原型版本:

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

用法:

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

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

Answer 12

你可以用一个简单的循环来做到这一点：

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