function compose (f, g) { return function(x) { return f(g(x)); } } var arr = [1, 2, 3], reverse = function(x){ return x.reverse()}, getFirst = function(x) {return x[0]}, compseFunc = compose(getFirst, reverse); compseFunc(arr); // 3 参数在函数间就好像通过‘管道’...
function getCss(element, attr) { if ('getComputedStyle' in window) { return window.getComputedStyle(element)[attr]; } return element.currentStyle[attr]; } 但是每次进这个方法都要做一下判断,为了提高性能,我们可以存一个变量,然后每次进去判断变量就好了 var flag = 'getComputedStyle' in window fun...
var compose = function(f,g) { return function(x) { return f(g(x)); }; }; 这就是函数组合(compose),f 和 g 都是函数, x是在它们之间通过“管道”传输的值。 我们可以通过组合函数使之产出一个崭新的函数: var toUpperCase = function(str) { return str.toUpperCase(); }; var exclaim = fun...
console.log(name.sort());//(5) ["amy", "catherine", "davina", "lily", "lisa"]//如果指明了compareFunction那数组会按照调用这个函数的返回值排序,比较函数格式如下:functioncompare(a, b) {if(ab) {return1; }//a=breturn0; }varnumbers=[1,2.3,5,0,9,8,10,34]; const num=numbers.so...
// refs: https://github.com/reduxjs/redux/blob/master/src/compose.tsfunctioncompose(...funcs:Function[]){if(funcs.length===0){// infer the argument type so it is usable in inference down the linereturn<T>(arg:T)=>arg}if(funcs.length===1){returnfuncs[0]}returnfuncs.reduce((a,b...
Compose new functions f(g(x)). Latest version: 3.0.3, last published: 10 years ago. Start using compose-function in your project by running `npm i compose-function`. There are 79 other projects in the npm registry using compose-function.
js编程中,我经常碰到一些函数式编程概念。函数式编程相关两个比较有名的库是:ramda.js 和 lodash.js,需要深入学习就必须去看看对应源码。下面记录一下: 柯里化 functionsum(x){returnfunction(y){returnx+y;}}sum(1)(2)// 3; 所谓柯里化,就是把一个多参数的函数转化为单一参数函数, curry 主要有 3 个...
If you are using ComposeJS in a CommonJS environment, you can load it: var Compose = require("compose"); Or an AMD module loader (RequireJS, Dojo, etc), you can load it: define(["compose"], function(Compose){ ... }); If ComposeJS is loaded as a plain script, it will create...
1. What is the purpose of the `_.compose` function in Underscore.js? A. To combine multiple functions into one B. To create a new array from an existing array C. To filter elements from a collection D. To sort a list of items Show Answer 2. How many functions can be ...
varmemoize=function(f){varcache={};returnfunction(){vararg_str=JSON.stringify(arguments);cache[arg_str]=cache[arg_str]||f.apply(f,arguments);returncache[arg_str];};};varsquareNumber=memoize(function(x){returnx*x;});squareNumber(4);//=> 16squareNumber(4);// 从缓存中读取输入值为 4...