轻松使用concat函数:

var a = [1,2,3];
var b = [2,3,4];
a = a.concat(b);
>> [1,2,3,2,3,4]

其中'n'是数组的个数，可能是数组的数组…

Var答案= _。Reduce (n, function(a, b){返回a.concat(b)})

似乎正确答案在不同的JS引擎中有所不同。以下是我从ninjagecko的答案中链接的测试套件中得到的结果:

[] .concat。apply在Windows和Android的Chrome 83中最快，其次是reduce(慢56%); 循环concat在Mac的Safari 13中是最快的，其次是reduce(大约慢13%); reduce在iOS上的Safari 12中是最快的，其次是循环concat(慢40%); elementwise push在Windows上的Firefox 70中最快，其次是[].concat。应用(速度慢30%)。

用Push合并数组:

Const array1 = [2,7,4]; Const array2 = [3,5,9]; array1.push(…array2); console.log (array1)

使用Concat和Spread运算符: Const array1 = [1,2]; Const array2 = [3,4]; //方法1:Concat Const combined1 =[]。concat (array1 array2); //方法二:Spread Const combined2 =[…]array1……array2); console.log (combined1); console.log (combined2);

现在我们可以使用ES6 Spread组合多个数组。 不要使用concat()来连接数组，而是尝试使用spread语法将多个数组组合成一个扁平数组。 例如:

var a = [1,2];
var b = [3,4];
var c = [5,6,7];
var d = [...a, ...b, ...c];
// resulting array will be like d = [1,2,3,4,5,6,7]

[].concat.apply([], [array1, array2, ...])

效率证明:http://jsperf.com/multi-array-concat/7

Tim Supinie mentions in the comments that this may cause the interpreter to exceed the call stack size. This is perhaps dependent on the js engine, but I've also gotten "Maximum call stack size exceeded" on Chrome at least. Test case: [].concat.apply([], Array(300000).fill().map(_=>[1,2,3])). (I've also gotten the same error using the currently accepted answer, so one is anticipating such use cases or building a library for others, special testing may be necessary no matter which solution you choose.)