Function extractSourceAndMap

lib/SourceMapDevToolPlugin.js:123–158

(file, asset, options, registry)

 * @returns {{ source: string, sourceMap: RawSourceMap, mapSource: Source } | undefined} extracted pair or `undefined` when no map is recoverable
 */
const extractSourceAndMap = (file, asset, options, registry) => {
	/** @type {string | Buffer} */
	let source;
	/** @type {null | RawSourceMap} */
	let sourceMap;
	if (asset.sourceAndMap) {
		const sourceAndMap = asset.sourceAndMap(options);
		source = sourceAndMap.source;
		sourceMap = sourceAndMap.map;
	} else {
		source = asset.source();
		sourceMap = asset.map(options);
	}
	class="cm">// Bail before touching the registry if we can't return a usable string
	class="cm">// source — pinning a non-string-producing asset would only waste the slot.
	if (typeof source !== class="st">"string") return;
	if (sourceMap) {
		class="cm">// The current asset still owns the original map — pin a reference so
		class="cm">// that a later plugin instance (which will see a rewrapped asset
		class="cm">// without a map) can recover it on demand.
		if (!registry.has(file)) registry.set(file, asset);
		return { source, sourceMap, mapSource: asset };
	}
	class="cm">// The current asset (typically a `RawSource` left by an earlier
	class="cm">// SourceMapDevToolPlugin instance) has no internal map. Re-extract
	class="cm">// the map from the original Source we pinned earlier. We keep using
	class="cm">// `source` from the current asset so that any prior wrappers (e.g.
	class="cm">// appended sourceMappingURL comments) are preserved.
	const original = registry.get(file);
	if (!original) return;
	sourceMap = original.sourceAndMap
		? original.sourceAndMap(options).map
		: original.map(options);
	if (!sourceMap) return;
	return { source, sourceMap, mapSource: original };
};

/**
 * Creating {@link SourceMapTask} for given file