JavaScript实现柯里化(curry)函数的思路和源码

const curry_fn = curry(fn);
fn(1, 2, 3) == curry_fn(1)(2)(3);

function curry(fn) {
    var length = fn.length; //获取原函数的参数个数
    var args = []; // args存储传入参数
    return function curryFn() {
        // 将arguments转换成数组
        var curryArgs = Array.prototype.slice.call(arguments); 
        args = args.concat(curryArgs);
        if (args.length > length) {
            throw new Error('arguments length error')
        }
        // 存储的参数个数等于原函数参数个数时执行原函数
        if (args.length === length) {
            return fn.apply(null, args);
        }
        // 否则继续返回函数
        return curryFn;
    };
}

function curry(fn) {
    let length = fn.length;
    let args = [];
    return function curryFn(...curryArgs) {
        args = args.concat(curryArgs);
        if (args.length > length) {
            throw new Error('arguments length error')
        }
        if (args.length === length) {
            return fn(...args);
        }
        return curryFn;
    }
}