node-version-call-local

Call a function in a Node version found in PATH.

This is a lightweight alternative to node-version-call that finds an existing Node in PATH rather than installing one. Use this when you need to execute code in a different Node version without the overhead of installation dependencies.

Installation

npm install node-version-call-local

Usage

Sync API (returns value, throws on error)

import { callSync, bindSync } from 'node-version-call-local';

// Immediate call - returns value synchronously
const result = callSync('>0.12', '/path/to/worker.js', {}, arg1, arg2);

// Bound caller for repeated use
const worker = bindSync('>0.12', '/path/to/worker.js', {});
const result1 = worker(arg1);
const result2 = worker(arg2);

Async API (callback or Promise)

import call, { bind } from 'node-version-call-local';

// With callback (last argument is function)
call('>0.12', '/path/to/worker.js', {}, arg1, (err, result) => {
  if (err) return console.error(err);
  console.log(result);
});

// With Promise (no callback)
const result = await call('>0.12', '/path/to/worker.js', {}, arg1);

// Bound caller with callback
const worker = bind('>0.12', '/path/to/worker.js', {});
worker(arg1, (err, result) => { /* ... */ });

// Bound caller with Promise
const result = await worker(arg1);

API

Sync Functions

callSync(version, workerPath, options?, ...args)

Execute a file synchronously in a Node version found in PATH.

• version - Semver constraint ('>0.12', '>=18', '^16') or exact ('v18.0.0')
• workerPath - Path to the file to execute
• options - Execution options (see below)
• args - Arguments to pass to the worker

Returns the result from the worker. Throws on error.

bindSync(version, workerPath, options?)

Create a bound caller for repeated synchronous use.

Returns a function (...args) => result that calls the worker.

Async Functions

call(version, workerPath, options?, ...args)

Execute a file asynchronously in a Node version found in PATH.

• If last argument is a function, it's treated as a callback: (err, result) => void
• Otherwise, returns a Promise

bind(version, workerPath, options?)

Create a bound caller for repeated async use.

Returns a function that:

• Takes a callback as last arg: (...args, callback) => void
• Or returns a Promise: (...args) => Promise<result>

Options

interface CallOptions {
  callbacks?: boolean;      // Worker uses callback style (default: false)
  spawnOptions?: boolean;   // Use spawnOptions for child process env setup (default: true)
  env?: NodeJS.ProcessEnv;  // Environment variables (default: process.env)
}

• callbacks - Set to true if the worker function uses callback style (fn(...args, callback)) rather than returning a value or Promise
• spawnOptions - When true, sets up proper environment (PATH, etc.) so child processes spawned by the worker use the correct Node version
• env - Custom environment variables to pass to the worker

Comparison with node-version-call

| Feature | node-version-call-local | node-version-call | |---------|---------------------------|-------------------| | Version not found | Throws error | Installs it | | Dependencies | Lightweight | Heavy (install chain) | | Version binding | At bind time | At call time | | Use case | Polyfills, bootstrap code | Testing, exact versions |

Example: HTTPS polyfill for old Node

import { callSync } from 'node-version-call-local';

const major = +process.versions.node.split('.')[0];
const noHTTPS = major === 0;

function fetchFileSync(url) {
  if (noHTTPS) {
    // Current Node can't do HTTPS, find one that can
    return callSync('>0', __filename, {}, url);
  }
  // Modern Node - fetch directly
  return fetchSync(url);
}

Example: Async with Promise

import call from 'node-version-call-local';

async function fetchData(url) {
  // Worker uses callback style internally
  const result = await call('>10', '/path/to/worker.js', { callbacks: true }, url);
  return result;
}

Example: npm install polyfill

import { bindSync } from 'node-version-call-local';

const major = +process.versions.node.split('.')[0];

// Worker that runs npm install
const workerPath = path.join(__dirname, 'workers', 'npmInstall.js');

// Need spawnOptions for npm environment
const npmInstall = bindSync('>10', workerPath, { spawnOptions: true });

function install(packageName) {
  if (major > 10) {
    // Current Node is fine
    return runNpmInstall(packageName);
  }
  // Use older Node found in PATH
  return npmInstall(packageName);
}

License

MIT