前言
如题，实现一些常用的函数，一个小练习；
内容
forEach
代码语言：javascript复制/**
* foreach
* @param {*} array
* @param {*} fn
*/
function forEach(array, fn) {
for (let index = 0; index < array.length; index ) {
fn(array[index])
}
}
// test
let array = [1,2,3,4,5]
forEach(array, function name(params) {
console.log(params);
})fliter
代码语言：javascript复制/**
* fliter
* @param {*} array
* @param {*} fn
* @returns
*/
function fliter (array, fn) {
let res = []
for (let index = 0; index < array.length; index ) {
if (fn(array[index])) {
res.push(array[index])
}
}
return res
}
// test
let arr = [1,2,3,4,5]
let r = fliter(arr, function name(params) {
return params % 2 === 0
})
console.log(r);makeFun
代码语言：javascript复制/**
* makeFun
* @param {*} params
* @returns
*/
function makeFn(params) {
let msg = "hello fn"
return function name(params) {
console.log(msg);
}
}
// test
const fn = makeFn()
fn()
makeFn()()once
代码语言：javascript复制/**
* once
* @param {*} fn
* @returns
*/
function once(fn) {
let done = false
return function name(params) {
if (!done) {
done = true
return fn.apply(this, arguments)
}
}
}
// test
let pay = once(function (money) {
console.log(`支付: ${money}`);
})
pay(5)
pay(4)
pay(3)map
代码语言：javascript复制/**
* map
* @param {*} array
* @param {*} fn
* @returns
*/
const map = (array, fn) => {
let res = []
for (const value of array) {
res.push(fn(value))
}
return res
}
// test
let arr = [1,2,3,4]
arr = map(arr, v => v * v )
console.log(arr);onece
代码语言：javascript复制/**
* every
* @param {*} array
* @param {*} fn
* @returns
*/
const every = (array, fn) => {
let res = []
for (const value of array) {
res = fn(value)
if (!res) {
break
}
}
return res
}
// test
let arr = [11,12,16, 1]
let r = every(arr, v => v > 10)
console.log(r);some
代码语言：javascript复制/**
* some
* @param {*} array
* @param {*} fn
* @returns
*/
const some = (array, fn) => {
let res = false
for (const value of array) {
res = fn(value)
if (res) {
break
}
}
return res
}
let arr = [1, 2, 3, 4]
let r = some(arr, v => v % 2 === 0)
console.log(r);
