hehehe/pr.html at master · someOneJYB/hehehe · GitHub

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<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
</head>
<body>

</body>
<script>
    class Promise {
        constructor(excutorCallBack){
            this.status = 'pending';
            this.value = undefined;
            this.fulfillAry = [];
            this.rejectedAry = [];
            let resolveFn = result => {
                if(this.status !== 'pending') return;
                this.status = 'fulfilled';
                this.value = result;
                let timer = setTimeout(() => {
                    this.fulfillAry.forEach(item=>item(this.value))
                }, 0);
            }
            let rejectedFn = reason => {
                if(this.value !== 'pedding') return;
                this.status = 'rejected';
                this.value = reason;
                let timer = setTimeout(() => {
                    this.rejectedAry.forEach(item=>item(this.value))
                }, 0);
            }
            try {
                excutorCallBack(resolveFn,rejectedFn)
            } catch(err) {
                rejectedFn(err)
            }
        }
        then(fulfilledCallBack,rejectedCallBack) {
            typeof fulfilledCallBack !== 'function' ? fulfilledCallBack = result => result : null;
            typeof rejectedCallBack !== 'function' ? rejectedCallBack = reason => {
                throw new Error(reason instanceof Error ? reason.message : reason)
            } : null;
            return new Promise((reslove, reject) => {
                if(this.status === 'fulfilled') {
                    let x = fulfilledCallBack(this.value);
                    x instanceof Promise ? x.then(reslove, reject):reslove(x)
                }
                if(this.status === 'rejected') {
                    let x = rejectedCallBack(this.value);
                    x instanceof Promise ? x.then(reslove, reject):reslove(x)
                }
                if(this.status === 'pending') {
                    this.fulfillAry.push(()=>{
                        try {
                            let x = fulfilledCallBack(this.value);
                            x instanceof Promise ? x.then(reslove, reject):reslove(x)
                        } catch(err) {
                            reject(err)
                        }
                    })
                    this.rejectedAry.push(()=>{
                        try {
                            let x = rejectedCallBack(this.value);
                            x instanceof Promise ? x.then(reslove,reject) : reslove(x);
                        } catch(err) {
                            reject(err);
                        }
                    })
                }
            })
        }
        catch(rejectedCallBack){
            return this.then(null,rejectedCallBack);
        }
        static resolve (value) {
            if (value instanceof Promise) return value
            return new Promise(resolve => resolve(value))
        }
    }
    var t1 = new Promise((resolve,rejected)=>{
        resolve('test');
    })
    // t1.then((value)=>{console.log(value)})
    setTimeout(()=>{
        let f = t1.then((value)=>{console.log(value);return new Promise(function(r, j){
            r('hehehe')
        })}).then((value)=>{console.log(value)})
        console.log(f)
    },3000);
</script>
</html>