md/js/高阶函数 curry.js

// fn(1)
// fn(2)
// fn(3)
// fn(4)
// fn(5)
// fn()
// console.log(1,2,3,4,5)
function isFunction(fn) {
    return Object.prototype.toString.call(fn)=== '[object Function]';
}


let fn = _curry(console.log,'test');
fn(1)
fn(2)
fn(3)
fn(4)
fn(5)
fn()

function _curry(fn){
    let _arguments = Array.from(arguments);
    let params = _arguments.splice(1);
    return function(){
        let __arguments = Array.from(arguments);
        if(__arguments.length >= 1){
            params.push(...__arguments);
        }else{
            return fn(...params,...arguments);
        }
    }
}
console.log('\n--------------------------------\n');
/**
 * @returns {(function(): (*))|*}
 */
 function curry(){
    let _arguments = Array.from(arguments);
    let runLength = null;
    let fn = null;
    let params = [..._arguments];
    let cb =  function (){
        let __arguments = Array.from(arguments);
        params.push(...__arguments);
        // 本次函数的参数
        // 历史函数的参数
        // 参数数量是否至少两个. 一般需要三个
        if(fn){
            // 空值执行
            if(__arguments.length<1 || (runLength && runLength <= params.length)){
                return fn(...params);
            }
            return cb;
        }
        // console.log(params);
        // 从输入中提取要执行的函数
        if(typeof params[0] === 'number' && isFunction(params[1])){
            runLength = params[0];
            fn = params[1];
            params = params.splice(2);
        }else if(isFunction(params[0])){
            runLength = null;
            fn = params[0];
            params = params.splice(1);
            if(fn.length){
                console.log(fn.length);
                runLength = fn.length;
            }
        }else if(typeof params[0] === 'number'){
            runLength = params[0];
            params = params.splice(1);
        }else{
            throw {message:'first param must function or number'}
        }
        // console.log(params);
        if(fn){
            if( runLength && runLength <= params.length){
                console.log('?');
                
                return fn(...params);
            }
        }
        return cb;
    }
    return cb;
}


function curry2(func) {
    return function curried(...args) {
      if (args.length >= func.length) {
        return func.apply(this, args);
      } else {
        return function(...args2) {
          return curried.apply(this, args.concat(args2));
        }
      }
    };
}

let c1 = function (event,msg){
    console.log(`event:${event} say ${msg}`)
}
let c2 = function (f1,f2,f3,f4){
    console.log(`1: ${f1}\n2: ${f2}\n3: ${f3}\n4: ${f4}`)
}
let c5 =function(){
    console.log(...arguments);
}

let fn1 = curry(c1,'test');
let r1 = fn1('你好1');
let r1_2 = fn1('你好2');
let r1_3 = fn1('你好3');
console.log('--------');
let fn2 = curry(4);
let r2 = fn2(c2)('a','b')('c','d');
console.log('--------');
let fn3 = curry(4,c2,'fn3 1','fn3 2');
let r3 = fn3('tes')('你好','9999999');
console.log('--------');
let fn4 = curry(2,console.log);
let r4 = fn4('fn4');
console.log('--------');
let fn5 = curry(c5);
let r5 = fn5('text555')('你好---')();
console.log('--------');