node-retrieve-globals

node-retrieve-globals

Execute a string of JavaScript using Node.js and return the global variable values and functions.

• Supported on Node.js 14 and newer.

• Uses var, let, const, function, Array and Object destructuring assignment.

• Async-friendly but synchronous methods are available.

• Can return any valid JS data type (including functions).

• Can provide an external data object as context to the local execution scope

• Uses Node’s vm module to execute JavaScript

  • ⚠️ The node:vm module is not a security mechanism. Do not use it to run untrusted code.
  • codeGeneration (e.g. eval) is disabled by default; use setCreateContextOptions({codeGeneration: { strings: true, wasm: true } }) to re-enable.

• In use on:

  • JavaScript in Eleventy Front Matter (and Demo)
  • WebC’s <script webc:setup>

Installation

Available on npm

npm install node-retrieve-globals

Usage

Works from Node.js with ESM and CommonJS:

import { RetrieveGlobals } from "node-retrieve-globals";
// const { RetrieveGlobals } = require("node-retrieve-globals");

And then:

let code = `var a = 1;
const b = "hello";

function hello() {}`;

let vm = new RetrieveGlobals(code);

await vm.getGlobalContext();

// or sync:
// vm.getGlobalContextSync();

Returns:

{ a: 1, b: "hello", hello: function hello() {} }

Pass in your own Data and reference it in the JavaScript code

let code = `let ref = myData;`;

let vm = new RetrieveGlobals(code);

await vm.getGlobalContext({ myData: "hello" });

// or sync:
// vm.getGlobalContextSync({ myData: "hello" });

Returns:

{ ref: "hello" }

Advanced options

// Defaults shown
let options = {
	reuseGlobal: false, // re-use Node.js `global`, important if you want `console.log` to log to your console as expected.
	dynamicImport: false, // allows `import()`
};

await vm.getGlobalContext({}, options);