code: public String[] toSourceArray(final JSModule module) {
      return runInCompilerThread(
          () -> {
            List<CompilerInput> inputs = module.getInputs();
            int numInputs = inputs.size();
            if (numInputs == 0) {
              return new String[0];
            }
  
            String[] sources = new String[numInputs];
            CodeBuilder cb = new CodeBuilder();
            for (int i = 0; i < numInputs; i++) {
              Node scriptNode = inputs.get(i).getAstRoot(Compiler.this);
              if (scriptNode == null) {
                throw new IllegalArgumentException("Bad module input: " + inputs.get(i).getName());
              }
  
              cb.reset();
              toSource(cb, i, scriptNode);
              sources[i] = cb.toString();
            }
            return sources;
          });
    }
docs: Converts the parse tree for each input in a module back to JS code.