How to append new array to beginning of multi

2018-06-06 05:00:42

This question already has an answer here:

How can I add new array elements at the beginning of an array in JavaScript? 6 answers

在这里，您可以使用解决方案https://jsfiddle.net/fkz9ubug/

var vArr = [[1, 1], [2, 3], [3, 3]];
var newv = [4, 4];
vArr.unshift(newv)

console.log(vArr);

The problem is with assigning the result of vArr.splice(0, 0, newv) back to vArr .

The splice function can also remove items from the array and the return value of splice() is those removed items.

So vArr = vArr.splice(0, 0, newv); should simply be vArr.splice(0, 0, newv); .

您可以使用unshift()在原始数组的开头推送新数组，并使用pop()从数组中移除最后一个元素：

var vArr = [[1, 1], [2, 2], [3, 3]];
var arrToPush = [4, 4];
vArr.unshift(arrToPush);
vArr.pop();
console.log(vArr);

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