今天,我们来一起学习一下如何把元素添加到数组的开头。
1.Array.unshift()
let fruits = [Apple, Banana, Mango]; fruits.unshift(Orange); console.log(fruits); // Prints [Orange, Apple, Banana, Mango] fruits.unshift(Guava, Papaya); console.log(fruits); // Prints [Guava, Papaya, Orange, Apple, Banana, Mango]
2.使用展开运算符(...)
var fruits = [Apple, Banana, Mango]; var moreFruits = [Orange, ...fruits]; console.log(moreFruits); // Prints [Orange, Apple, Banana, Mango] var someoMoreFruits = [Guava, Papaya, ...moreFruits]; console.log(someoMoreFruits); // Prints [Guava, Papaya, Orange, Apple, Banana, Mango] console.log(fruits); // Prints [Apple, Banana, Mango]
3.使用 Array.concat()
我们还可以使用concat()
方法在开头连接两个(或更多)数组。
var fruits = [Apple, Banana, Mango]; var moreFruits = [Orange]; var someoMoreFruits = [Guava, Papaya]; var allFruits = someoMoreFruits.concat(moreFruits, fruits); console.log(allFruits); // Prints [Guava, Papaya, Orange, Apple, Banana, Mango]
原文地址:https://codingnconcepts.com/javascript/how-to-add-element-at-beggining-of-javascript-array/
作者:Orkhan Jafarov
译文地址:https://segmentfault.com/a/1190000039129785
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