const arr = [1, 2, 3, 4, 5]
for循环
for (let i = 0; i < arr.length; i++) {
console.log(arr[i])
}
for (let i = 0; i < arr.length; i++) {
if (arr[i] === 2) {
continue
}
console.log(arr[i])
}
forEach循环
arr.forEach(function (item) {
console.log(item)
})
every循环
arr.every(function (item) {
console.log(item)
return true
})
arr.every(function (item) {
console.log(item)
})
arr.every(function (item) {
if (item === 2) {
return false
} else {
console.log(item)
return true
}
})
arr.every(function (item) {
if (item === 2) {
} else {
console.log(item)
}
return true
})
for in 循环
for (let index in arr) {
if (index * 1 === 2) {
continue
}
console.log(index, arr[index])
}
for of循环
for (let item of arr) {
console.log(item)
}
const Price = {
A: [1.5, 2.3, 4.5],
B: [3, 4, 5],
C: [0.5, 0.8, 1.2],
}
for (let key in Price) {
console.log(key, Price[key])
}
let args = [].slice.call(arguments)
let imgs = [].slice.call(document.querySelectorAll('img'))
console.log(args)
Array.prototype.from
let args = Array.from(arguments)
let imgs = Array.from(document.querySelectorAll('img'))
imgs.forEach()
Array.from(arrayLike,mapFn,thisArg)
let array = Array(5)
for (let i = 0, len = array.length; i < len; i++) {
array[i] = 1
}
cosole.log(array)
let array = Array.from({ length: 5 }, function () {
return 1
})
console.log(array)
Array.prototype.of
let array = Array.of(1)
console.log(array)
Array.prototype.fill
let array = Array(5).fill(1)
console.log(array
Array.fill(value,start,end)
let array = [1, 2, 3, 4, 5]
console.log(array.fill(8, 2, 4))
let array = [1, 2, 3, 4, 5]
let find = array.filter(function (item) {
return item % 2 === 0
})
console.log(find)
Array.prototype.find
let find = array.find(function (item) {
return item % 2 === 0
})
console.log(find)
Array.prototype.findIndex
let array = [1, 2, 3, 4, 5]
let find = array.findIndex(function (item) {
return item % 2 === 0
})
console.log(find)