for_await_track_reactivity_loss() — svelte Function Reference

Architecture documentation for the for_await_track_reactivity_loss() function in async.js from the svelte codebase.

Function javascript ClientRuntime Reactivity calls 1

Entity Profile

ClientRuntime→ Reactivity→ for_await_track_reactivity_loss() — svelte Function Reference

Dependency Diagram

graph TD
  87a0d652_5594_9e6c_5ae4_5b99c4d138f0["for_await_track_reactivity_loss()"]
  1ad3e508_c069_abae_2e4a_bd17c8892e18["async.js"]
  87a0d652_5594_9e6c_5ae4_5b99c4d138f0 -->|defined in| 1ad3e508_c069_abae_2e4a_bd17c8892e18
  3cead1b0_a9df_a632_11a8_a235eac55668["track_reactivity_loss()"]
  87a0d652_5594_9e6c_5ae4_5b99c4d138f0 -->|calls| 3cead1b0_a9df_a632_11a8_a235eac55668
  style 87a0d652_5594_9e6c_5ae4_5b99c4d138f0 fill:#6366f1,stroke:#818cf8,color:#fff

Relationship Graph

Source Code

packages/svelte/src/internal/client/reactivity/async.js lines 175–208

export async function* for_await_track_reactivity_loss(iterable) {
	// This is based on the algorithms described in ECMA-262:
	// ForIn/OfBodyEvaluation
	// https://tc39.es/ecma262/multipage/ecmascript-language-statements-and-declarations.html#sec-runtime-semantics-forin-div-ofbodyevaluation-lhs-stmt-iterator-lhskind-labelset
	// AsyncIteratorClose
	// https://tc39.es/ecma262/multipage/abstract-operations.html#sec-asynciteratorclose

	/** @type {AsyncIterator<T, TReturn>} */
	// @ts-ignore
	const iterator = iterable[Symbol.asyncIterator]?.() ?? iterable[Symbol.iterator]?.();

	if (iterator === undefined) {
		throw new TypeError('value is not async iterable');
	}

	/** Whether the completion of the iterator was "normal", meaning it wasn't ended via `break` or a similar method */
	let normal_completion = false;
	try {
		while (true) {
			const { done, value } = (await track_reactivity_loss(iterator.next()))();
			if (done) {
				normal_completion = true;
				break;
			}
			yield value;
		}
	} finally {
		// If the iterator had a normal completion and `return` is defined on the iterator, call it and return the value
		if (normal_completion && iterator.return !== undefined) {
			// eslint-disable-next-line no-unsafe-finally
			return /** @type {TReturn} */ ((await track_reactivity_loss(iterator.return()))().value);
		}
	}
}