Wyvern

0.2.0 verified Fri May 01 auth: no javascript

wyvern is a reactive JavaScript transpiler that compiles reactive syntax into standard JavaScript. At version 0.2.0, it is in early development with an unstable API. It differentiates itself by providing a declarative reactive programming model that compiles to efficient vanilla JS, targeting developers who want reactivity without a runtime library. The package is meant to be used as a build tool (transpiler) and is not designed for runtime use. Release cadence is unknown as the project is new.

Common errors

error ERR_REQUIRE_ESM ↓

cause Using require() to import an ESM-only package.

fix

Replace require('wyvern') with import statements or use dynamic import.

error TypeError: wyvern.compile is not a function ↓

cause Default import or wrong import path.

fix

Use named import: import { compile } from 'wyvern';

Warnings

breaking API is unstable and may change without notice in versions < 1.0.0. ↓

fix Pin to exact version and expect breaking changes.

gotcha Package is ESM-only; CommonJS require will fail with ERR_REQUIRE_ESM. ↓

fix Use ES module syntax (import) or dynamic import() in CommonJS projects with bundler.

gotcha compile() options may be incomplete; check documentation for supported options. ↓

fix Supply only sourceType if unsure; options object may be ignored.

Install

npm install wyvern

yarn add wyvern

pnpm add wyvern

Imports

compile

wrong

const wyvern = require('wyvern'); const compile = wyvern.compile;

correct

import { compile } from 'wyvern';

Package is ESM-only; CommonJS require will not work.

default (module)
wrong
```
const wyvern = require('wyvern');
```
correct
```
import wyvern from 'wyvern';
```
Default export may not exist; prefer named imports.
transform
```
import { transform } from 'wyvern';
```
Check if transform is exported; version 0.2.0 may have limited exports.

Quickstart

Shows how to use the compile function to transpile a source file, with error handling.

import { compile } from 'wyvern';
import { readFileSync, writeFileSync } from 'fs';

const source = readFileSync('input.js', 'utf8');
try {
  const output = compile(source, { sourceType: 'module' });
  writeFileSync('output.js', output.code, 'utf8');
} catch (e) {
  console.error('Compilation failed:', e.message);
}