高仿race

var b = new Promise((reslove, reject) => {
    setTimeout(() => {
        reslove(1232)
    }, 3000)
})

Promise.krace = function (org) {
    // count = 0;
    return new Promise((resolve, reject) => {
        org.forEach((item, index) => {
            Promise.resolve(item).then(res => {
                // count++;
                // if (count == org.length) {
                resolve(res)
                // }
            })
        });
    })
}
Promise.krace([a, b]).then(res => {
    console.log(res, '--res--')
})

高仿all

Promise.kall = function (org) {
    let arr = []
    let count = 0;
    return new Promise((resolve, reject) => {
        org.forEach((item, i) => {
            Promise.resolve(item).then(res => {
                arr[i] = res
                count++;
                if (count == org.length) resolve(arr)
            })
        });
    })
}

Promise.kall([a, b]).then(res => {
    console.log(res, '----res---')
})

高仿promise

class kPromise {
    status = 'PADDING' //FAILED SUCCESS
    result = null;
    Arrays = []
    constructor(obj) {
        obj(this.resolve.bind(this), this.reject.bind(this))
    }

    resolve(item) {
        this.status = 'SUCCESS'
        this.result = item;
        this.Arrays.forEach((one, ind) => {
            one['succ'](this.result)
        })
    }

    reject(item) {
        this.status = 'FAILED';
        this.result = item;

        this.Arrays.forEach((one, ind) => {
            if (!one.full) throw Error('没有写这个reject函数');
            one['full'](this.result)
        })
    }

    then(onsucc, onfulled) {
        return new Promise((reslove, reject) => {
            if (this.status == 'PADDING') {
                let obj = {
                    'succ': (one) => {
                        onsucc(one);
                        reslove(one)
                    }
                }
                onfulled ? obj.full = (one) => {
                    onsucc(one);
                    reslove(one)
                } : null;
                this.Arrays.push(obj)
            }
            if (this.status == 'SUCCESS') {
                onsucc(this.result)
            }
            if (this.status == 'FAILED') {
                onfulled(this.result)
            }
        })
    }
}

new kPromise((resolve, reject) => {
        setTimeout(() => {
            reject(12321)
        }, 3000)
    }).then(res => {
        console.log(res,'---reject--')
    },(req)=>{
        console.log(req,'----req--')
    })
    .then(res => {
        console.log(res, '---')
    })