push与concat

push

push()方法将一个或多个元素添加到数组的末尾，并且返回新的数组长度。

语法：

arr.push(element1, ..., elementN)

concat

concat() 方法用于连接两个或多个数组。该方法不会改变现有的数组，而仅仅会返回被连接数组的一个副本。

语法：

var new_array = old_array.concat(value1[, value2[, ...[, valueN]]])

因此，push与concat的对原数组的操作是不同的，push是在原数组基础上操作的，而concat的原数组不会改变。

//push
var sports = ['soccer', 'baseball'];
var total = sports.push('football', 'swimming');

console.log(sports); // ['soccer', 'baseball', 'football', 'swimming']
console.log(total);  // 4

//concat
var sports = ['soccer', 'baseball'];
var total = sports.concat('football', 'swimming');

console.log(sports); // ['soccer', 'baseball']
console.log(total);  // ['soccer', 'baseball','football', 'swimming']

添加长度大于1的数组,push会将数组作为整体添加到数组末尾，而concat则不会

//push
var sports = ['soccer', 'baseball'];
var total = sports.push(['football', 'swimming']);

console.log(sports); //["soccer", "baseball", Array[2]]0: "soccer"1: "baseball"2: Array[2]length: 3__proto__: Array[0]

console.log(total);  // 3

//concat
var sports = ['soccer', 'baseball'];
var total = sports.concat(['football', 'swimming']);

console.log(sports); // ["soccer", "baseball"]

console.log(total);  // ["soccer", "baseball", "football", "swimming"] 

那么在上一步的操作中如何使用push方法，使sports变成["soccer", "baseball", "football", "swimming"] ，而不是["soccer", "baseball", Array[2]]？^[1]

首先push和concat均可使用call()和Apply(), 其中

apply()方法能劫持另外一个对象的方法，继承另外一个对象的属性.

Function.apply(obj,args)方法能接收两个参数
obj：这个对象将代替Function类里this对象
args：这个是数组，它将作为参数传给Function（args-->arguments）

call()和apply的意思一样,只不过是参数列表不一样.

Function.call(obj,[param1[,param2[,…[,paramN]]]])
obj：这个对象将代替Function类里this对象
params：这个是一个参数列表

从Apply()的定义上，你大概已经知道解决方法了，利用Apply，将数组作为参数传给push,这样就能得到你想要的结果了。

var sports = ['soccer', 'baseball'];
var total = Array.prototype.push.apply(sports,['football', 'swimming']);

/*or
var total = sports.push.apply(sports,['football', 'swimming']);
*/

console.log(sports); // ["soccer", "baseball", "football", "swimming"] 
console.log(total);  // 4

相关链接：

[1] stackoverflow  How to extend an existing JavaScript array with another array? [duplicate]