code: function encodeLastRecordedSourceMapSpan() {
              if (!lastRecordedSourceMapSpan || lastRecordedSourceMapSpan === lastEncodedSourceMapSpan) {
                  return;
              }
              var prevEncodedEmittedColumn = lastEncodedSourceMapSpan.emittedColumn;
              // Line/Comma delimiters
              if (lastEncodedSourceMapSpan.emittedLine === lastRecordedSourceMapSpan.emittedLine) {
                  // Emit comma to separate the entry
                  if (sourceMapData.sourceMapMappings) {
                      sourceMapData.sourceMapMappings += ",";
                  }
              }
              else {
                  // Emit line delimiters
                  for (var encodedLine = lastEncodedSourceMapSpan.emittedLine; encodedLine < lastRecordedSourceMapSpan.emittedLine; encodedLine++) {
                      sourceMapData.sourceMapMappings += ";";
                  }
                  prevEncodedEmittedColumn = 1;
              }
              // 1. Relative Column 0 based
              sourceMapData.sourceMapMappings += base64VLQFormatEncode(lastRecordedSourceMapSpan.emittedColumn - prevEncodedEmittedColumn);
              // 2. Relative sourceIndex
              sourceMapData.sourceMapMappings += base64VLQFormatEncode(lastRecordedSourceMapSpan.sourceIndex - lastEncodedSourceMapSpan.sourceIndex);
              // 3. Relative sourceLine 0 based
              sourceMapData.sourceMapMappings += base64VLQFormatEncode(lastRecordedSourceMapSpan.sourceLine - lastEncodedSourceMapSpan.sourceLine);
              // 4. Relative sourceColumn 0 based
              sourceMapData.sourceMapMappings += base64VLQFormatEncode(lastRecordedSourceMapSpan.sourceColumn - lastEncodedSourceMapSpan.sourceColumn);
              // 5. Relative namePosition 0 based
              if (lastRecordedSourceMapSpan.nameIndex >= 0) {
                  ts.Debug.assert(false, "We do not support name index right now, Make sure to update updateLastEncodedAndRecordedSpans when we start using this");
                  sourceMapData.sourceMapMappings += base64VLQFormatEncode(lastRecordedSourceMapSpan.nameIndex - lastEncodedNameIndex);
                  lastEncodedNameIndex = lastRecordedSourceMapSpan.nameIndex;
              }
              lastEncodedSourceMapSpan = lastRecordedSourceMapSpan;
              sourceMapData.sourceMapDecodedMappings.push(lastEncodedSourceMapSpan);
          }
docs: Encoding for sourcemap span