Function transformer

transformer(handler, postHandler?): ts.TransformerFactory<ts.Bundle | ts.SourceFile>
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) => any)
  A function to process AST nodes.
  - - (data): any
    - Parameters
      data: {
      node: Node;
      sourceFile: SourceFile;
      }
      node: Node
      sourceFile: SourceFile
      Returns any
- Optional postHandler: ((sourceFile) => SourceFile)
  A function to postprocess the source file after all nodes visited. Return an updated SourceFile node.
  - - (sourceFile): SourceFile
    - Parameters
      sourceFile: SourceFile
      Returns SourceFile
Returns ts.TransformerFactory<ts.Bundle | ts.SourceFile>
JSDoc custom "meta-transformer".