Syntaxase

Lightning-fast type stripping and JSX lowering.

Named like an enzyme, Syntaxase removes erasable TypeScript syntax and lowers supported TypeScript and JSX runtime constructs.

Install

npm install syntaxase

Usage

import { stripTypes, transform } from "syntaxase";

const stripped = stripTypes(`
interface User { name: string }
const user: User = { name: "Ada" };
`);

const transformed = transform(`const view: JSX.Element = <h1>Hello</h1>;`, { jsx: true });

TypeScript syntax

stripTypes erases fixed-width TypeScript syntax while preserving source length and line layout. Use it with source accepted by TypeScript's erasableSyntaxOnly option. It does not validate that constraint: runtime TypeScript constructs such as enums may remain unchanged or lose TypeScript-only modifiers without gaining the JavaScript code needed to preserve their semantics.

transform additionally lowers supported runtime TypeScript constructs and, when enabled, JSX.

JSX options

| options.jsx | Behavior | Defaults and supported fields | | -------------------------- | ------------------------------------------------- | --------------------------------------------------------------- | | omitted or false | Parse TypeScript without JSX | None | | true | Lower JSX with the automatic production runtime | importSource: "react" | | { runtime: "automatic" } | Lower JSX with the automatic runtime | development: false, importSource: "react" | | { runtime: "classic" } | Lower JSX to factory calls without adding imports | pragma: "React.createElement", pragmaFrag: "React.Fragment" | | { runtime: "preserve" } | Parse JSX and leave it in the output | No additional fields |

Automatic development mode imports jsxDEV from <importSource>/jsx-dev-runtime; production mode imports jsx and jsxs from <importSource>/jsx-runtime. The default therefore requires React's JSX runtime to be installed. Set importSource for another compatible runtime.

development is supported only by the automatic runtime. pragma and pragmaFrag are supported only by the classic runtime.

Diagnostics and errors

The JavaScript API returns transformed strings only. Parser recovery diagnostics are not exposed, so malformed input can still produce output. Use a TypeScript checker or another parser when validation is required. Invalid API arguments and internal transform failures throw.