const p1 = new Promise(resolve => {
	setTimeout(() => {
		resolve(1)
	}, 1000)
})
const p2 = new Promise(resolve => {
	setTimeout(() => {
		resolve(2)
	}, 1000)
})

Promise.all2 = function(promises) {
	const len = promises.length
	console.log(len)
	return new Promise((resolve, reject) => {
		const results = []
		let count = 0
		for (let i = 0; i < len; i++) {
			// Promise.resolve 包一下是为了防止传递过来的不是个 Promise 的情况
			Promise.resolve(promises[i]).then(
				data => {
					count++
					results[i] = data
					if (count === len) resolve(results)
				},
				err => {
					return reject(err)
				}
			)
		}
	})
}

// Promise.all2([ p1, p2 ]).then(r => {
// 	console.log(r)
// })

Promise.race2 = function(promises) {
	return new Promise(function(resolve, reject) {
		for (let i = 0; i < promises.length; i++) {
			Promise.resolve(promises[i]).then(
				data => {
					resolve(data)
				},
				err => {
					return reject(err)
				}
			)
		}
	})
}

Promise.race2([ p1, p2 ]).then(r => {
	console.log(r)
})