Function transformChunk

src/utils/renderChunks.ts:109–200

(
	magicString: MagicStringBundle,
	fileName: string,
	usedModules: Module[],
	chunkGraph: Record<string, RenderedChunk>,
	options: NormalizedOutputOptions,
	outputPluginDriver: PluginDriver,
	log: LogHandler
)

}

async function transformChunk(
	magicString: MagicStringBundle,
	fileName: string,
	usedModules: Module[],
	chunkGraph: Record<string, RenderedChunk>,
	options: NormalizedOutputOptions,
	outputPluginDriver: PluginDriver,
	log: LogHandler
) {
	let map: SourceMap | null = null;
	const sourcemapChain: DecodedSourceMapOrMissing[] = [];
	let code = await outputPluginDriver.hookReduceArg0(
		'renderChunk',
		[magicString.toString(), chunkGraph[fileName], options, { chunks: chunkGraph }],
		(code, result, plugin) => {
			if (result == null) return code;

			if (typeof result === 'string')
				result = {
					code: result,
					map: undefined
				};

			// strict null check allows 'null' maps to not be pushed to the chain, while 'undefined' gets the missing map warning
			if (result.map !== null) {
				const map = decodedSourcemap(result.map);
				sourcemapChain.push(map || { missing: true, plugin: plugin.name });
			}

			return result.code;
		}
	);
	const {
		compact,
		dir,
		file,
		sourcemap,
		sourcemapExcludeSources,
		sourcemapFile,
		sourcemapPathTransform,
		sourcemapIgnoreList
	} = options;
	if (!compact && code[code.length - 1] !== '\n') code += '\n';

	if (sourcemap) {
		timeStart('sourcemaps', 3);

		let resultingFile: string;
		if (file) resultingFile = resolve(sourcemapFile || file);
		else if (dir) resultingFile = resolve(dir, fileName);
		else resultingFile = resolve(fileName);

		const decodedMap = magicString.generateDecodedMap({});
		map = collapseSourcemaps(
			resultingFile,
			decodedMap,
			usedModules,
			sourcemapChain,