await 在 forEach 中不生效解决方案

function test() {
	let arr = [3, 2, 1]
	arr.forEach(async item => {
		const res = await fetch(item)
		console.log(res)
	})
	console.log('end')
}

function fetch(x) {
	return new Promise((resolve, reject) => {
		setTimeout(() => {
			resolve(x)
		}, 500 * x)
	})
}

test()

async function test() {
	let arr = [3, 2, 1]
	await Promise.all(
		arr.map(async item => {
			const res = await fetch(item)
			console.log(res)
		})
	)
	console.log('end')
}

async function test() {
	let arr = [3, 2, 1]
	for (const item of arr) {
		const res = await fetch(item)
		console.log(res)
	}
	console.log('end')
}

async function test() {
	let arr = [3, 2, 1]
	const iterator = arr[Symbol.iterator]()
	let res = iterator.next()
	while (!res.done) {
		const value = res.value
		const res1 = await fetch(value)
		console.log(res1)
		res = iterator.next()
	}
	console.log('end')
}