Recipe for passing parameters to tasks by binding TaskFunctions

[roydukkey]

I know this is a very tired subject, but I have some thoughts and possibly a valid use case.

As far I can tell, gulp doesn't ever use this for TaskFunctions. Therefore, it is possible do the following:

package.json

{
  "build": {
    "clean": {
      "sass": "./Web/wwwroot/themes/**/*.css",
      "typescript": "./Web/wwwroot/themes/**/*.js"
    },
    "sass": {
      "source": "./Web/themes/**/*.sass",
      "destination": "./Web/wwwroot/themes"
    },
    "typescript": {
      "source": "./Web/themes/**/main.ts",
      "destination": "./Web/wwwroot/themes"
    }
  }
}

Clean.ts

import type { TaskFunction } from 'gulp';
import { build } from '../package.json';
import del from 'del';

const config = Object.values(build.clean);

const task: TaskFunction = async function (this: string[] | undefined, /* done */) {
  return del(this ?? config);
  // done() is still functions, if needed.
};

export default task;

Watch.ts

import Clean from './Clean';
import Sass from './Sass';
import type { TaskFunction } from 'gulp';
import TypeScript from './TypeScript';
import { build } from '../package.json';
import { series, watch } from 'gulp';

const cleanSass = Clean.bind([build.clean.sass]);
const cleanTypeScript = Clean.bind([build.clean.typescript]);

cleanTypeScript.displayName =
cleanSass.displayName = 'watch;clean';

const task: TaskFunction = () => {
  watch(build.sass.source, series(cleanSass, Sass));
  watch(build.typescript.source, series(cleanTypeScript, TypeScript));
};

export default task;

gulpFile.ts

import Clean from './build/Clean';
import Sass from './build/Sass';
import TypeScript from './build/TypeScript';
import Watch from './build/Watch';
import { parallel } from 'gulp';

Sass.displayName = 'build:sass';
TypeScript.displayName = 'build:ts';

const build = parallel(Sass, TypeScript);

Watch.displayName = 'watch';
Clean.displayName = 'clean';

export { build, Sass, TypeScript, Watch, Clean };

I have seen other approaches for passing around arguments, but those suggestions all require:

• wrapping/additional functions
• exporting internal tasks to implement arguments with yargs or similar

Additionally, if would be possible to bind anything or type to the this argument. So, the recipe could even suggest multiple argument by simply binding an object (eg. .bind({ arg1, arg2, ... }).

So...

1. Is the this argument on TaskFunctions truly unused at the moment?
2. Does gulp have plans to implement the this argument on TaskFunctions in the future for anything else?
3. Is there anything else I'm might be overlooked.

[phated]

This is almost exactly what https://github.com/gulpjs/undertaker-task-metadata does. You can create a registry that uses similar logic but takes a config and binds it to each task based on name.

Registries were designed to defer low-level, opinionated behavior, like this, to the consumer.

The caveat is that registries don't work perfectly with task exports. We could definitely use someone looking into that.