code: public void addMapping(Mapping aArgs) {
          Position generated = aArgs.generated;
          Position original = aArgs.original;
          String source = aArgs.source;
          String name = aArgs.name;
  
          if (source != null && !this._sources.has(source)) {
              _sources.add(source, false);
          }
          if (name != null && !this._names.has(name)) {
              _names.add(name, false);
          }
          _mappings.add(new Mapping(generated, original, source, name));
      }
docs: Add a single mapping from original source line and column to the generated source's line and column for this source map being created. The
  mapping object should have the following properties:
  <ul>
  <li>generated: An object with the generated line and column positions.</li>
  <li>original: An object with the original line and column positions.</li>
  <li>source: The original source file (relative to the sourceRoot).</li>
  <li>name: An optional original token name for this mapping.</li>
  </ul>