Node Compatibility Mode seems to have been removed

[robert-commonsku]

In version 1.25 of deno, node compatibility mode (https://deno.land/[email protected]/node/compatibility_mode) seems to have been replace by Experimental npm support (https://deno.com/blog/v1.25#experimental-npm-support).

[kitsonk]

The manual is going through an extensive re-write, including addressing this gap.

@bartlomieju though we should have pulled the documentation from the manual when we removed the feature.

[traceypooh]

oh sh*t - so the node deno run --compat mode got removed?

I was just about to file a bug since I can't make it work per the manual.

I was hoping to see if any baseline eslint worked any better today, and to see if could help with a wanted jsdom type setup for testing => https://github.com/denoland/deno-docs/issues/98

[bartlomieju]

Yes it was removed, but you can run eslint like so: deno run -A --unstable npm:eslint

[traceypooh]

yes, indeed thank you!

and this is fantastic -- much better.

however, there this issue making it so various plugins -- or even any kind of config, really -- cant be used yet

https://github.com/denoland/deno/issues/15845

I've hand coded a single JS file that does this kind of thing:

#!/usr/bin/env -S deno run -A --unstable

import { ESLint } from "npm:eslint"

...


(async function main() {
  // 1. Create an instance.
  const eslint = new ESLint(cfg);

  // 2. Lint files.
  const results = await eslint.lintFiles(Deno.args);
  // console.error({ results });

  // 3. Format the results.
  const formatter = await eslint.loadFormatter('stylish');
  const resultText = formatter.format(results);

  // 4. Output it.
  console.log(resultText);
  if (resultText)
    Deno.exit(1);
})().catch((error) => {
  console.error(error);
  Deno.exit(1);
});

And that gets me around the "cant read eslint config files" (read perms) issue. But I can't load in any eslint plugins for similar read perms issues.

If we could get the -A and --allow-read portion to work and allow reading files everywhere, best i can tell everything will work.

[bartlomieju]

Thanks for the comment. We'll be looking into this issue after tomorrow's release.

[traceypooh]

ok, i wont lie, i've been feverishly waiting to hear if anything coming ASAP (gave it a long shot, but... ;) )

but wait! holy sh*t twinkies!

I just got LESS => CSS compiling working via npm:less usage for something else in our monorepo that am migrating node => deno...

... and was reviewing the release notes between v1.25, v1.26, and v1.27 (after having some minor issues w/ v1.25x)

https://deno.com/blog/v1.26#improvements-to-npm-support

ooooh snap!

I just found the --node-modules-dir option.

So now I got eslint and plugins and base config -- everything for us, totally working! <3 As I think you may recall from prior posts for over a year, I've been hoping for some kind of hobbled full eslint setup (and have a bunch of workarounds now) for a 30,000+ line JS repo I moved to deno.

I dont have to tell you -- and you can tell from my excitement ;) -- that this changes everything for us and I suspect many many more folks.

I'm sure this node compat mode was internally hugely controversial for you folks -- but for a very small number of crazy useful things we and other "cant live without"... this is so huge. 🙏

Here's the .eslintrc.cjs we're using common to many projects, with all the base & plugins & rules we want

https://github.com/internetarchive/dyno/blob/main/.eslintrc.cjs

Here's both a eslint CLI script (chmod 755) that we can lint itself to showcase it all working:

#!/usr/bin/env -S deno run -A --unstable --node-modules-dir

/* eslint-disable import/no-unresolved */

import 'npm:eslint-plugin-compat'
import 'npm:eslint-plugin-import'
import 'npm:eslint-config-airbnb-base'
import 'npm:eslint-plugin-no-floating-promise'
import { ESLint } from 'npm:eslint';

// eslint-disable-next-line wrap-iife
(async function main() {
  // 1. Create an instance.
  const eslint = new ESLint({
    rulePaths: [],
    extensions: null,
    ignore: true,
    cache: false,
    fix: false,
    allowInlineConfig: true,
    globInputPaths: true,
  })

  // 2. Lint files.
  const results = await eslint.lintFiles(Deno.args)
  // console.error({ results })

  // 3. Format the results.
  const formatter = await eslint.loadFormatter('stylish')
  const resultText = formatter.format(results)

  // 4. Output it.
  console.log(resultText)
  if (resultText)
    Deno.exit(1)
})().catch((error) => {
  console.error(error)
    Deno.exit(1)

})

copy in our .eslintrc.cjs file into same dir as script (avoids that "read permissions" issue mentioned above):

and voila!

> ./eslint.js eslint.js

/Volumes/bff/dev/x/eslint.js
  33:3   warning  Unexpected console statement                  no-console
  37:3   warning  Unexpected console statement                  no-console
  38:1   error    Expected indentation of 2 spaces but found 4  indent
  38:17  error    Block must not be padded by blank lines       padded-blocks

✖ 4 problems (2 errors, 2 warnings)
  2 errors and 0 warnings potentially fixable with the `--fix` option.

🙏 🙏 🙏

[traceypooh]

Even better / simpler, we're doing this kind of setup now:

wget https://raw.githubusercontent.com/internetarchive/dyno/main/.eslintrc.cjs

echo '  console.log( "  hi")'  >  index.js

# get all our wanted plugins
deno cache --unstable --node-modules-dir  \
  npm:eslint-config-airbnb-base  \
  npm:eslint-plugin-compat  \
  npm:eslint-plugin-import  \
  npm:eslint-plugin-no-floating-promise

deno run -A --unstable --node-modules-dir  npm:eslint  .                                                               

  1:1   error    Expected indentation of 0 spaces but found 2  indent
  1:3   warning  Unexpected console statement                  no-console
  1:15  error    There should be no space after this paren     space-in-parens
  1:16  error    Strings must use singlequote                  quotes

✖ 4 problems (3 errors, 1 warning)
  3 errors and 0 warnings potentially fixable with the `--fix` option.

[bartlomieju]

Thanks for investigation @traceypooh! I'll be talking with ESLint maintainer soon and we'll see if there's something we could do to improve the situation for Deno users.

[traceypooh]

thanks!

two minor things I noticed (FWIW):

• if the eslint emits errors, it doesnt exit non-0 like the node CLI does. so i have to wrap w/ a scripts call to capture the output (and nice coloring) and then check it to know if should error out (our velociraptor scripts)
• lots of spurious cb warnings at the end of the run. so i pipe all stderr to /dev/null