message: Reindent lib/mappings.ts to use two spaces per tab.
diff: @@ -29,12 +29,10 @@ const Mapping = function Mapping(this: MappingType, sourceLines: any, sourceLoc:
  // In certain cases it's possible for targetLoc.{start,end}.column
  // values to be negative, which technically makes them no longer
  // valid SourceLocation nodes, so we need to be more forgiving.
  - assert.ok(
  - isNumber.check(targetLoc.start.line) &&
  + assert.ok(isNumber.check(targetLoc.start.line) &&
  isNumber.check(targetLoc.start.column) &&
  isNumber.check(targetLoc.end.line) &&
  - isNumber.check(targetLoc.end.column)
  - );
  + isNumber.check(targetLoc.end.column));
  } else {
  // Assume identity mapping if no targetLoc specified.
  targetLoc = sourceLoc;
  