ekwoka/vite-plugin-using

Vite Plugin to transpile the using keyword

A quick and easy way to start using USING today!

Note: This project is deprecated! The behavior is easily accessible inside of VITE using `esbuild.target: 'es2022' which will be a lot better than this dirty package anyway.

This plugin allows using the upcoming JS keyword using in your code today! It transpiles using and await using to try/finally blocks to get the same effect more easily!

Installation

pnpm add vite-plugin-using

Add to your vite.config.ts

import ViteUsing from 'vite-plugin-using';

export default defineConfig({
  plugins: [ViteUsing()],
});

You will need to polyfill the new @@dispose and @@asyncDispose symbols as such somewhere in your runtime:

Symbol.dispose ??= Symbol('@@dispose');
Symbol.asyncDispose ??= Symbol('@@asyncDispose');

Usage

Just start using!!

class disposable {
  constructor() {}
  [Symbol.dispose]() {
    console.log('disposing')
  }
  [Symbol.asyncDispose]() {
    console.log('async disposing')
  }
}

{
  using obj = new disposable();
  console.log('made one obj');
  await using obj2 = new disposable();
  console.log('made two obj');
  console.log(obj, obj2)
}

Dang That's Cool!

vite-plugin-using's Issues

Line breaks seem to cause this plugin to break

The following code works using this plugin:

const comparator = (x: Point) => x.x - point[timestampColumnName];
using searchRes = binarySearch(this.highchartSeries!.points, comparator);

The following code does not work:

using searchRes = binarySearch(
    this.highchartSeries!.points,
    (x: Point) => x.x - point[timestampColumnName],
);

It generates the following error:

11:10:36 PM [vite] Internal server error: 
  × Expression expected
     ╭─[file.ts:323:1]
 323 │                         
 324 │       const searchRes = binarySearch(
 325 │                             
 326 │       try {
     ·       ───
 327 │         this.highchartSeries!.points,
 328 │                             (x: Point) => x.x - point[timestampColumnName],
 329 │                         );
     ╰────


Caused by:
    Syntax Error
  Plugin: vite:react-swc
  File: file.ts:323:1
  

[TypeScript] Found 0 errors. Watching for file changes.

From the error, it seems like the transpiled try block is starting on the wrong line.

Deprecate in favor of `esbuild.target: 'es2022'`

As mentioned in vitejs/vite#14327 (comment)

{
  esbuild: {
    target: 'es2022'
  }
}

properly transforms using statements using an AST, which prevents bugs such as #2.

It would be best to mark this project as deprecated, with a note about the correct configuration.