将两个数组合并到一个数组中

var array1 = [1, 2, 3];
var array2 = [4, 5, 6];
var mergedArray = array1.concat(array2);
console.log(mergedArray);

var array1 = [1, 2, 3];
var array2 = [4, 5, 6];
var mergedArray = [...array1, ...array2];
console.log(mergedArray);

var array1 = [1, 2, 3];
var array2 = [4, 5, 6];
array2.forEach(function(element) {
  array1.push(element);
});
console.log(array1);

var array1 = [1, 2, 3];
var array2 = [4, 5, 6];
Array.prototype.splice.apply(array1, [array1.length, 0].concat(array2));
console.log(array1);