SOURCE

const PENDING = 'pending'
const FULFILLED = 'fulfilled'
const REJECTED = 'rejected'

class MyPromise {
    constructor(executor) {
        executor(this.resolvue, this.reject)
    }

    status = PENDING
    value = null
    reason = null

    resolvue = (value) => {
        if(this.status === PENDING) {
            this.status = FULFILLED
            this.value = value
        }
    }

    reject = (reason) => {
        if(this.status === PENDING) {
            this.status = REJECTED
            this.reason = reason
        }
    }

    then(onFulfilled,onRejected) {
        if(this.status === FULFILLED) {
            onFulfilled(this.value)
        } else if(this.status === REJECTED) {
            onRejected(this.reason)
        }
    }
}

module.export = MyPromise;