[TS tranformer] TS tranformer for codemod #typescript #codemod #ast

transform.ts

function transformer<T extends ts.Node>(): ts.TransformerFactory<T> {
  return context => {
    const visit: ts.Visitor = node => {
      switch (node.kind) {
        case ts.SyntaxKind.Parameter:
          if (!(node as any).type) {
            const newNode = ts.createParameter(
              (node as ts.ParameterDeclaration).decorators,
              (node as ts.ParameterDeclaration).modifiers,
              (node as ts.ParameterDeclaration).dotDotDotToken,
              (node as ts.ParameterDeclaration).name,
              (node as ts.ParameterDeclaration).questionToken,
              ts.createTypeReferenceNode('TodoAny', []),
              (node as ts.ParameterDeclaration).initializer
            )
            return newNode
          }
          return node
        default:
          return ts.visitEachChild(node, child => visit(child), context)
      }
    }

    return node => ts.visitNode(node, visit)
  }
}

const result = ts.transform(sourceFile, [transformer<ts.SourceFile>()], {})