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JavaScript创建指定数量的重复元素

· One min read
Alan

JavaScript中，如果创建重复的元素, 原问题: https://stackoverflow.com/questions/12503146/create-an-array-with-same-element-repeated-multiple-times

下面的场景是创建一个数组，数组里包含5个重复的元素2:

Array.from​

Array.from({ length: 5 }).map(x => 2)
Array.from({ length: 5 }, i => 2) 
Array.from({ length: 5 }, (e, i) => i)  // => 0, 1, 2, 3, 4

fill​

Array(5).fill(2)

Array.apply​

Array.apply(null, Array(5)).map(() => 2)

Expand​

[...Array(5)].map(() => 2)

join + split​

Array(5).join("2").split("")

flat​

Array(3).fill(['a','b','c']).flat()  // => Array(9) [ "a", "b", "c", "a", "b", "c", "a", "b", "c" ]