SOURCE

const a = fetch('http://localhost:10003/api/sys_user/login', {
    method: 'post',
    headers: { 'Content-Type': 'application/json' },
    body: JSON.stringify({ name: '1', password: '1' })
})
const b = fetch('http://localhost:10003/api/sys_user/login', {
    method: 'post',
    headers: { 'Content-Type': 'application/json' },
    body: JSON.stringify({ name: '1', password: '1' })
})

Promise.pAll = function(arr) {
    return new Promise((resolve, reject) => {
        const result = []
        for (p of arr) {
            p.then(res => {
                result.push(res)
                if (result.length === arr.length) {
                    resolve(result)
                }
            }).catch(err => {
                reject(err)
            })
        }
    })
}

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