如何在 JS 中的數組開頭添加元素?

做者：Orkhan Jafarov
譯者：前端小智
來源: dev

今天，咱們來一塊兒學習一下如何把元素添加到元素的首個元素。

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.使用展開運算符(...)

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()

咱們還能夠使用concat()方法在開頭鏈接兩個(或更多)數組。

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"]

完~我是小智，我要去刷碗了，咱們下期再見~

---

代碼部署後可能存在的BUG無法實時知道，過後爲了解決這些BUG，花了大量的時間進行log 調試，這邊順便給你們推薦一個好用的BUG監控工具 Fundebug。

原文：https://codingnconcepts.com/j...

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