抄大佬一个Promise.all

Promise.myAll = function(proms) {
    let res, rej
    const p = new Promise((resolve, reject) => {
        res = resolve
        rej = reject
    })
    let i = 0
    const result = []
    for(let pro of proms) {
        const idx = i
        i ++
        Promise.resolve(pro).then(data => {
            result[idx] = data
            i --
            if(i === 0) {
                res(result)
            }
        }, rej)
    }
    if(i === 0) {
        res([])
    }
    return p
} 

Promise.myAll([1,2,Promise.reject(5),3,4]).then(res => {
    console.log(res);  
}).catch(e => {
    console.log(e);
})