Is it possible to get the javascript output from ts-node?

[bediu]

Obviously ts-node transpiles into javascript first. Is it possible to access this javascript somehow, before it gets fed into node?

[agammann]

Yes. The programmatic API exposes create() and the service's compile() method, so you can get the emitted JavaScript without executing the TypeScript source:

const { create } = require('ts-node');
const fs = require('node:fs');
const path = require('node:path');

const filename = path.resolve('example.ts');
const source = fs.readFileSync(filename, 'utf8');
const service = create();
const javascript = service.compile(source, filename);

fs.writeFileSync('example.js', javascript);
console.log(javascript);

Run this as node compile.cjs from your project directory. create() selects the project's ts-node/TypeScript configuration from the current working directory. The absolute filename passed to compile() locates the source and its relative imports; it does not select a different project configuration. The returned text includes the source map generated by ts-node.

I tested this with ts-node 10.9.2: the : number annotation in example.ts disappeared from the output, and the resulting CommonJS example.js ran separately. This compiles one file; it does not bundle imported modules. See the programmatic API.