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

``bash
npm install node-version-call-local
`

Usage

$3

`javascript
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);
`

$3

`javascript
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

$3

#### 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.

$3

#### 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

$3

`typescript
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

`javascript
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

`javascript
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

`javascript
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