Method parse

src/valdi_modules/src/valdi/source_map/src/SourceMap.ts:123–222

(sourceMapJson: string)

  }

  static parse(sourceMapJson: string): SourceMap {
    const object = JSON.parse(sourceMapJson) as SourceMapJson;
    if (object.version !== 3) {
      throw new Error('SourceMap version must be 3');
    }

    if (!object.mappings) {
      throw new Error('Missing mappings');
    }

    let sources = object.sources ?? [];
    const names = object.names ?? [];

    sources = sources.map(source => {
      // Remove leading '/'
      if (source.charAt(0) === '/') {
        source = source.substr(1);
      }

      return source;
    });

    /**
      Logic ported from https://github.com/microsoft/sourcemap-toolkit/blob/master/src/SourcemapToolkit.SourcemapParser/MappingListParser.cs
       */

    const lines: MappedLine[] = [];
    const allMappings = object.mappings.split(';');

    let generatedLineNumber = 0;
    let generatedColumnNumber = 0;
    let sourcesListIndex = 0;
    let originalLineNumber = 0;
    let originalColumnNumber = 0;
    let namesListIndex = 0;

    for (const mappings of allMappings) {
      const segments = mappings.split(',');
      const entries: MappedLineEntry[] = [];

      for (const segment of segments) {
        if (!segment) {
          continue;
        }

        const fields = decode(segment);

        if (fields.length !== 1 && fields.length !== 4 && fields.length !== 5) {
          throw new Error(`Invalid mappings (found ${fields.length} fields in ${segment})`);
        }

        generatedColumnNumber += fields[0];

        let originalFileName: string | undefined;

        if (fields.length > 1) {
          sourcesListIndex += fields[1];
          originalLineNumber += fields[2];