Promises and async/await

JavaScript is single-threaded: long operations (network, files, browser commands) don't block execution — the result comes back "later" via a Promise.

A Promise has 3 states: pending → fulfilled (success) or rejected (error).

async/await is the modern, readable way to work with Promises:

• an async function always returns a Promise
• await waits for the Promise to settle and unwraps the value
• in Playwright nearly every command returns a Promise: await page.click(...), await page.goto(...)

Parallel waiting: await independent Promises in parallel, not sequentially:

• Promise.all([p1, p2]) — waits for all; if one rejects, the whole thing rejects
• Promise.allSettled([...]) — returns every outcome (success/failure mixed)
• Promise.race([...]) — returns the first to settle (useful for timeout patterns)