前端之编程训练——Compose

[jyzwf]

var arr = [func1, func2, func3];
function func1(ctx, next) {
    ctx.index++
    next();
}
function func2(ctx, next) {
    setTimeout(function () {
        ctx.index++;
        next();
    });
}
function func3(ctx, next) {
    console.log(ctx.index);
}

const compose = arr => arr.reverse().reduce((a, b) => obj => b(obj, () => a(obj)), () => { })
compose(arr)({ index: 0 }); // 输出：2

/*
function compose(arr) {
    return arr.reverse().reduce((a, b) => {
        return function (obj) {
            b(obj, function () {
                a(obj)
            })
        }
    }, () => { })
}
*/