Promise.all /用于等待并获取它的查询数组

Question

Can i

array.push(fetch(`something`))

For execution in Promise.all / for await, or

fetch(`something`)

execute itself before i push it in array and not further in code when i want it?

---

More info:

Let assume i need to do many queries with for await (if i want to execute them one after another) or Promise.all (if i want to execute them async together).

I make an queries array:

let queries = []
let allResults = []

Push there promises:

tiersQueries.push(fetch(`something`))

And them execute it like this:

for await (const oneResult of queries) {
 allResults.push(oneResult)
}

Or this:

let results = await Promise.all(array)
allResults = results

Answer 1

The way promises work, they will immediately start executing when created, but they store their status (resolved or rejected or pending) so that even .then or .catch handlers attached after they are completed will still fire. Similarly, Promise.all just waits for all the promises to be resolved, it doesn't care whether they were resolved before you passed them .all . That means you're perfectly fine pushing all the fetches to an array and using Promise.all to attach resolution handlers for processing the results of all of them whenever they complete (even if they all complete before the .all runs).