Function encodeMappings

lib/util/createMappings.js:69–115

(lines)

 * @returns {string} VLQ-encoded V3 mappings string
 */
const encodeMappings = (lines) => {
	let prevSourceIndex = 0;
	let prevOriginalLine = 0;
	let prevOriginalColumn = 0;
	let prevNameIndex = 0;

	const encodedLines = [];

	for (const line of lines) {
		if (line === null || line === undefined) {
			encodedLines.push("");
			continue;
		}

		const segments = Array.isArray(line) ? line : [line];
		let prevGeneratedColumn = 0;
		const encodedSegments = [];

		for (const segment of segments) {
			const generatedColumn = segment.generatedColumn || 0;
			let encoded = encodeVLQ(generatedColumn - prevGeneratedColumn);
			prevGeneratedColumn = generatedColumn;

			if (segment.sourceIndex !== undefined) {
				const originalLine = /** @type {number} */ (segment.originalLine);
				const originalColumn = /** @type {number} */ (segment.originalColumn);
				encoded += encodeVLQ(segment.sourceIndex - prevSourceIndex);
				encoded += encodeVLQ(originalLine - prevOriginalLine);
				encoded += encodeVLQ(originalColumn - prevOriginalColumn);
				prevSourceIndex = segment.sourceIndex;
				prevOriginalLine = originalLine;
				prevOriginalColumn = originalColumn;

				if (segment.nameIndex !== undefined) {
					encoded += encodeVLQ(segment.nameIndex - prevNameIndex);
					prevNameIndex = segment.nameIndex;
				}
			}

			encodedSegments.push(encoded);
		}

		encodedLines.push(encodedSegments.join(","));
	}

	return encodedLines.join(";");
};

module.exports.encodeMappings = encodeMappings;
module.exports.encodeVLQ = encodeVLQ;