本文已經過原作者 Orkhan Jafarov 授權翻譯。
今天,我們來一起學習一下如何把元素新增到元素的首個元素。
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.使用展開運算子(...)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()我們還可以使用concat()方法在開頭連線兩個(或更多)陣列。
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,我們下期再見~
原文:https://codingnconcepts.com/javascript/how-to-add-element-at-beggining-of-javascript-array/
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