Function getSourceMapFromUrl

lib/processors/minifier.js:86–122

({sourceMappingUrl, resourcePath, readFile})

}

async function getSourceMapFromUrl({sourceMappingUrl, resourcePath, readFile}) {
	// =======================================================================
	// This code is almost identical to code located in lbt/bundle/Builder.js
	// Please try to update both places when making changes
	// =======================================================================
	if (sourceMappingUrl.startsWith("data:")) {
		// Data-URI indicates an inline source map
		const expectedTypeAndEncoding = "data:application/json;charset=utf-8;base64,";
		if (sourceMappingUrl.startsWith(expectedTypeAndEncoding)) {
			const base64Content = sourceMappingUrl.slice(expectedTypeAndEncoding.length);
			// Create a resource with a path suggesting it's the source map for the resource
			// (which it is but inlined)
			return Buffer.from(base64Content, "base64").toString();
		} else {
			log.warn(
				`Source map reference in resource ${resourcePath} is a data URI but has an unexpected` +
				`encoding: ${sourceMappingUrl}. Expected it to start with ` +
				`"data:application/json;charset=utf-8;base64,"`);
		}
	} else if (httpPattern.test(sourceMappingUrl)) {
		log.warn(`Source map reference in resource ${resourcePath} is an absolute URL. ` +
			`Currently, only relative URLs are supported.`);
	} else if (posixPath.isAbsolute(sourceMappingUrl)) {
		log.warn(`Source map reference in resource ${resourcePath} is an absolute path. ` +
			`Currently, only relative paths are supported.`);
	} else {
		const sourceMapPath = posixPath.join(posixPath.dirname(resourcePath), sourceMappingUrl);

		try {
			const sourceMapContent = await readFile(sourceMapPath);
			return sourceMapContent.toString();
		} catch (e) {
			// No input source map
			log.warn(`Unable to read source map for resource ${resourcePath}: ${e.message}`);
		}
	}
}

/**
 * @public