javascript - 如何检查数组在 javascript 中是否相等？

Question

看看这个代码示例 or go to the jsfiddle

function printRelation(a, b, out) {
    var text;
    if (a === b) {
        text = "a === b";
    } else if (a == b) {
        text = "a == b";
    } else {
        text = "a != b";
    }
    $('#' + out).text(text);
}

var a = [0, 0, 2], b = a;
printRelation(a, b, 'out1');
a = [0, 0, 2];
b = [0, 0, 2];
printRelation(a, b, 'out2');

我希望两个测试都能输出 a === b，但只有第一个会输出。第二个输出 a != b。谁能解释这种行为？如何在 javascript 中高效地比较数组？

Answer 1

您可以使用 Underscore.js 库的 isEqual 方法。

http://underscorejs.org/#isEqual

Performs an optimized deep comparison between the two objects, to determine if they should be considered equal.

var moe   = {name : 'moe', luckyNumbers : [13, 27, 34]};
var clone = {name : 'moe', luckyNumbers : [13, 27, 34]};
moe == clone;
=> false
_.isEqual(moe, clone);
=> true

---

更新

Lodash 的灵感来自下划线，但现在是更好的解决方案

https://lodash.com/docs/#isEqual

Performs an optimized deep comparison between the two objects, to determine if they should be considered equal.

var object = { 'a': 1 };
var other = { 'a': 1 };

_.isEqual(object, other);
// => true

object === other;
// => false