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How Top Level Await Works in JavaScript
- Top-level await in JavaScript only works in ES modules, not in regular scripts, and requires parsing as an ES module in browsers or using .mjs extension or 'type': 'module' in Node.js.
- If await is used outside an async function in a classic script, a syntax error occurs immediately.
- Module execution pauses for top-level await until the awaited promise settles, affecting the entire module's execution and any importing modules.
- The module system adds an execution barrier for top-level await, causing a delay in the import process until the awaited value is resolved.
- Top-level await changes module loading process by introducing asynchronous pauses without wrapping everything in a function.
- Circular dependencies with top-level await are more strictly managed in modern runtimes to prevent unresolved deadlocks.
- To avoid issues with top-level await and circular dependencies, it's crucial to consider the order of operations and isolate async work inside exported functions.
- Engine splits module loading into parsing, setup, and execution phases, holding execution when encountering a top-level await to maintain consistency.
- Top-level await provides a more natural coding order but introduces an execution barrier until the awaited value is ready.
- Modern JavaScript modules behave with timing constraints due to top-level await, affecting the flow of execution and module imports.
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