僞數組轉數組的幾種方式

將類數組轉換未數組的幾種方法

1. Array.prototype.slice.call()

function sum(a,b,c) {
    let args = Array.prototype.slice.call(arguments)
    console.log(args.reduce((sum, cur) => sum + cur))
}
sum(1 + 3 + 4)  //8

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 2.Array.form()

function sum2(...args) {
    let arg = Array.from(arguments)
    console.log(arg.reduce((sum, cur) => sum + cur))
}
sum2(1,3,4) //8
// 這種方法也能夠用來轉換Set和Map

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3.ES6 展開運算符

function sum(a, b) {
    let args = [...arguments]
    console.log(args.reduce((sum, cur) => sum + cur))
}
sum(1,3) // 4

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4.利用 concat + apply

function sum(a,b) {
    let args = Array.prototype.concat.apply([], arguments)
    console.log(args.reduce((sum, cur) => sum + cur))
}

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5.for ... in 循環

function sum (a,b) {
    let args = []
    for(i in arguments) {
        args.push(arguments[i])
    }
    console.log(args.reduce((sum, cur) => sum + cur))
}
sum(1,3) // 4

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6.for ... of 循環

 function sum (a, b) {
     let args = []
     for( item of arguments) {
        args.push(item)
     }
     console.log(args.reduce((sum, cur) => sum + cur))
 }

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