Function transformer

transformer(
    handler: (
        data: {
            context: TransformationContext;
            node: Node;
            sourceFile: SourceFile;
        },
    ) => any,
    postHandler?: (sourceFile: SourceFile) => SourceFile,
): TransformerFactory<SourceFile | Bundle>
Provides a convenient "meta-transformer" that invokes a handler function for each Node reducing the boilerplate required.

Note: In the handler return null to remove the Node. The postHandler allows final modification of the SourceFile after all nodes are visited; return a new SourceFile to update it.
Parameters
- handler: (
      data: {
          context: TransformationContext;
          node: Node;
          sourceFile: SourceFile;
      },
  ) => any
  A function to process AST nodes.
- OptionalpostHandler: (sourceFile: SourceFile) => SourceFile
  A function to postprocess the source file after all nodes visited. Return an updated SourceFile node.
Returns TransformerFactory<SourceFile | Bundle>
JSDoc custom "meta-transformer".