curry&unCurry函数

unCurry函数与curry函数区别：
curry化函数：固定部分参数，返回一个接受剩余参数的新函数，目的是为了缩小适用范围，创建一个针对性更强的函数。
unCurry化函数：扩大适用范围，创建一个应用范围更广的函数。使本来只有特定对象才适用的方法，扩展到更多的对象。

unCurry函数  参考：https://www.cnblogs.com/pigtail/p/3450852.html   https://juejin.im/post/5b561426518825195f499772#heading-7

方法一：
class Toast{
    constructor(){
        this.prompt=''
    }
    show(){
        console.log(this.prompt);
    }
}
var temObj={prompt:'tem'}
Toast.prototype.show.call(temObj)

function unCurry(fn){
    return function(context){
        var args=Array.prototype.slice(1)||[];
        fn.apply(context,args)
    }
}

var unCurryShow=unCurry(Toast.prototype.show);
unCurryShow(temObj)

方法2
Function.prototype.unCurrying = function(){
    var self = this;
    return function(){
        return Function.prototype.call.apply(self, arguments);
    }
    //return this.call.bind(this);
}

// 使用
var objShow = Toast.prototype.show.unCurrying();
objShow(obj);

应用：

Function.prototype.unCurry=function(){
    return this.call.bind(this)
}
var objPush=Array.prototype.push.unCurry();
var temObj={};
objPush(temObj,'a','b')  

var toUpperCase = String.prototype.toUpperCase.unCurrying();
console.log(toUpperCase('avd')); // AVD

function AryUpper(ary) {
    return ary.map(toUpperCase);
}

console.log(AryUpper(['a', 'b', 'c'])); // ["A", "B", "C"]

var call = Function.prototype.call.unCurrying();
function $(id) {
    return this.getElementById(id);
}
var demo = call($, document, 'demo');
console.log(demo);

//Function.prototype.call.call(fn,context,...args)

var objToString=Object.prototype.toString.unCurry()
var fn1=function(){}
objToString(objToString)

curry化 参考：https://juejin.im/post/5bf9bb7ff265da616916e816

function myCurry(fn){
        if(fn.length<=1)return fn;
        let generator=function(...args){
            return (args.length === fn.length?fn(...args):function(...arg){return generator(...args,...arg)})
        };
        return generator()
    }

参考:https://juejin.im/post/5cef46226fb9a07eaf2b7516#heading-11

带占位符的curry
function curry(fn){
        let placeHolder='_';
        if(fn.length<=1)return fn
        function generator(oldArgs=[],newArgs){
            oldArgs.forEach((item,ind,arr)=>{
                if(item==placeHolder){
                    let spliceIndx=newArgs.findIndex(newArg=>newArg!==placeHolder)
                    arr[ind]=newArgs.splice(spliceIndx,1)[0]
                }
            })
            Array.prototype.push.apply(oldArgs,newArgs)
            let realArgs=oldArgs.filter(item=>item!==placeHolder);
            if(realArgs.length===fn.length){
                return fn(...realArgs)
            }else if(realArgs.length===fn.length){
                throw new Error('超出初始函数参数最大值')
            }else{
               return (...newArgs)=>{return generator(oldArgs,newArgs)}
            }

        }
        return generator()
    }

　　function arr(a,b,c,d){
　　　return [a,b,c,d]
　　}