code: public String[] toSourceArray() {
      return runInCompilerThread(
          () -> {
            Tracer tracer = newTracer("toSourceArray");
            try {
              int numInputs = moduleGraph.getInputCount();
              String[] sources = new String[numInputs];
              CodeBuilder cb = new CodeBuilder();
              int i = 0;
              for (CompilerInput input : moduleGraph.getAllInputs()) {
                Node scriptNode = input.getAstRoot(Compiler.this);
                cb.reset();
                toSource(cb, i, scriptNode);
                sources[i] = cb.toString();
                i++;
              }
              return sources;
            } finally {
              stopTracer(tracer, "toSourceArray");
            }
          });
    }
docs: Converts the parse tree for each input back to JS code.