ftst

library1.2.2jsnpmunverified

ftst (v1.2.2) is a minimal TypeScript transpiler that removes type annotations from TypeScript files, leaving readable JavaScript where the output is line-by-line equivalent to the input. This eliminates the need for source maps during debugging. It supports only ES2019, ES2020, and ESNext script targets, and offers a command-line runner (node -r ftst filename.ts) as well as JS API functions transpileModule and transpile. Compared to tsc or other transpilers, ftst focuses solely on type stripping without full compilation, making it extremely fast and suitable for quick type removal tasks or debugging scenarios. It is dependency-free and works in Node.js environments.

serialization

npm install ftst

github ↗package ↗

INSTALL

IMPORT

SIG · FTST

ftst

serializationjavascriptv1.2.2

harness data pending

Install & Compatibility

Where this runs

No compatibility data collected yet for this library.

Code

Verified usage

Verified import paths — ran on the pinned version, not inferred.

transpileModule

✓ import { transpileModule } from 'ftst/transpiler'

✗ import ftst from 'ftst'; ftst.transpileModule(...)

The function is exported from 'ftst/transpiler', not from the main 'ftst' package (the main export is a CommonJS module).

transpile

✓ import { transpile } from 'ftst/transpiler'

✗ const { transpile } = require('ftst/transpiler');

The package is ESM-only? Actually, it supports both CJS and ESM. The example uses require, but for ESM use the named import.

ModuleKind

✓ import { ModuleKind } from 'ftst/transpiler'

✗ const { ModuleKind } = require('ftst');

Enums like ModuleKind and ScriptTarget are exported from 'ftst/transpiler', not from the main module.

ScriptTarget

✓ import { ScriptTarget } from 'ftst/transpiler'

Part of the transpiler module alongside ModuleKind.

Demonstrates using transpileModule to strip types from a TypeScript interface and function, returning clean JavaScript.

import { transpileModule, ModuleKind, ScriptTarget } from 'ftst/transpiler'; const source = ` interface Person { name: string; age: number; } function greet(person: Person): string { return `Hello, ${person.name}!`; } `; const options = { compilerOptions: { target: ScriptTarget.ES2020, module: ModuleKind.CommonJS, removeComments: false, noEmitHelpers: true, preserveConstEnums: true, noImplicitUseStrict: true, newLine: 'lf', downlevelIteration: true, suppressExcessPropertyErrors: true }, reportDiagnostics: true }; const result = transpileModule(source, options, true); console.log(result.outputText); // Expected output: function greet(person) { return 'Hello, ' + person.name + '!'; }

ftst --version

Debug

Known issues

gotchaOnly ES2019, ES2020, and ESNext script targets are supported. Using other targets may produce incorrect output or errors.

fix

Set compilerOptions.target to ScriptTarget.ES2019, ScriptTarget.ES2020, or ScriptTarget.ESNext.

affects: >=0.0.0

gotchaThe main module export (require('ftst')) may not expose the transpile functions directly. Use 'ftst/transpiler' instead.

fix

Import from 'ftst/transpiler' for transpileModule, transpile, and enums.

affects: >=0.0.0

gotchaThe remove parameter in transpileModule affects whether types are commented out or fully removed. When true, types are stripped entirely; when false, they are replaced with comments.

fix

Set remove to true to avoid commented types in output.

affects: >=0.0.0

breakingNo major breaking changes reported; however, the package is minimal and may not handle all TypeScript syntax (e.g., advanced type constructs or decorators).

fix

Test your code thoroughly; consider using full tsc for complex TypeScript features.

affects: >=0.0.0

Errors

Common errors & fixes

Cannot find module 'ftst/transpiler'

Typo or incorrect path; correct path is 'ftst/transpiler'.

fix

Ensure you import from 'ftst/transpiler' (not 'ftst/transpile' or 'ftst').

TypeError: ftst.transpileModule is not a function

Importing from wrong module (main 'ftst' instead of 'ftst/transpiler') or using default import incorrectly.

fix

Use: import { transpileModule } from 'ftst/transpiler';

Unsupported target 'ES5' specified. Only ES2019, ES2020, ESNext are allowed.

Setting unsupported script target in compilerOptions.

fix

Set target to one of: ScriptTarget.ES2019, ScriptTarget.ES2020, ScriptTarget.ESNext.

Upgrade

Version history

1.2.2latest on npm

Audit

Dependencies

No dependency data recorded yet.

Agent activity

2 hits · last 30 days

node

Resources

githubhttps://github.com/mkslanc/ftst ↗

packagehttps://www.npmjs.com/package/ftst ↗