with with

A simple way to use the JavaScript with statement in strict mode!

This is not a sandbox do not use it as a sandbox do not try to make it a sandbox. We will try this and fail so you don't have to.

Installation

Node/Bun

pnpm install with-with

Deno

import withWith from "https://deno.land/x/with/mod.ts";

QuickJS

Cry.

Usage

let accessible = false;
const returnValue = withWith(
    { hello: "there" },
    () =>
        ({ hello }) => {
            // You can get types via destructuring like `() => ({ hello, ...etc }) =>`.

            // Logs `there`.
            console.log("hello", hello);

            // Variables from the parent scope are still accessible and can be mutated.
            accessible = true;

            // You can return as well and it will get passed back to the upper scope.
            return hello;
        },
    // This lifter enables your with wrapped function to be able to access all variables from the parent scope.
    { lifter: (k) => eval(k) }
);
console.log(returnValue, accessible);

Binding

withWith(
    { hello: "there" },
    () =>
        function () {
            console.log(this);
        },
    // No variables from the parent scope are accessed, so there's no need for a lifter.
    { binding: { on: "this" } }
);

Why `() => () =>`?

To get around duplicate variable names in subscopes, some JS engines cough cough v8 simply rename them and all the references. This breaks the binding to the orginal object when you destructure to make TypeScript happy.