number-transformer

number-transformer.ts

const source = `
  const two = 2;
  const four = 4;
`;

function numberTransformer<T extends ts.Node>(): ts.TransformerFactory<T> {
  return context => {
    const visit: ts.Visitor = node => {
      if (ts.isNumericLiteral(node)) {
        return ts.createStringLiteral(node.text);
      }
      return ts.visitEachChild(node, child => visit(child), context);
    };

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

let result = ts.transpileModule(source, {
  compilerOptions: { module: ts.ModuleKind.CommonJS },
  transformers: { before: [numberTransformer()] }
});

console.log(result.outputText);

/*
  var two = "2";
  var four = "4";
*/