aegir lint complaints about imports in ts files

[Gozala]

Describe the bug

As the following pull request illustrates multiformats/js-multiaddr#131 aegir lint complains about imports in ts files.

As far as I can tell that happens because it lints .ts files

aegir/src/lint.js

Lines 9 to 20 in 2fe4403

	const FILES = [
	'*.{js,ts}',
	'bin/**',
	'config/**/*.{js,ts}',
	'test/**/*.{js,ts}',
	'src/**/*.{js,ts}',
	'tasks/**/*.{js,ts}',
	'benchmarks/**/*.{js,ts}',
	'utils/**/*.{js,ts}',
	'!**/node_modules/**',
	'!**/*.d.ts'
	]

With JS configuration unless global ts option is used
https://github.com/ipfs/aegir/blob/master/src/lint.js#L86

This creates problems in cases where project combination of .ts and .js files.

I'm not too familiar with ESLint, but as far as I can tell there's no way to specify different parseOptions per file type

aegir/src/config/eslintrc-ts.js

Lines 5 to 7 in 2fe4403

	parserOptions: {
	sourceType: 'module'
	},

[Gozala]

@hugomrdias could we leave out .ts files from eslint and let the TSC do the linting there ? I think TS supports plenty of rules to disallow unused vars, params, implicit this, return, etc...

[Gozala]

Actually it looks like overrides could be used to provide different rules based on file type https://eslint.org/docs/user-guide/configuring#specifying-processor

[Gozala]

Following local .eslintrc seems to resolve aegir lint problem:

{
  "overrides": [
    {
      "files": [
        "**/*.ts"
      ],
      "extends": "./node_modules/aegir/src/config/eslintrc-ts.js"
    },
    {
      "files": [
        "**/*.js"
      ],
      "extends": "./node_modules/aegir/src/config/eslintrc.js"
    }
  ]
}

But now I see problem when running tests

aegir test                                 ✗ ✱
Test Node.js
Warning: Cannot find any files matching pattern "test/node.{js,ts}"

/Users/gozala/Projects/js-multiaddr/test/types.spec.ts:1
import Multiaddr from "../src";
^^^^^^

SyntaxError: Cannot use import statement outside a module
    at wrapSafe (internal/modules/cjs/loader.js:1054:16)
    at Module._compile (internal/modules/cjs/loader.js:1102:27)
    at Object.Module._extensions..js (internal/modules/cjs/loader.js:1158:10)
    at Module.load (internal/modules/cjs/loader.js:986:32)
    at Function.Module._load (internal/modules/cjs/loader.js:879:14)
    at Module.require (internal/modules/cjs/loader.js:1026:19)
    at require (internal/modules/cjs/helpers.js:72:18)
    at Object.exports.requireOrImport (/Users/gozala/Projects/js-multiaddr/node_modules/mocha/lib/esm-utils.js:20:12)
    at Object.exports.loadFilesAsync (/Users/gozala/Projects/js-multiaddr/node_modules/mocha/lib/esm-utils.js:33:34)
    at async singleRun (/Users/gozala/Projects/js-multiaddr/node_modules/mocha/lib/cli/run-helpers.js:156:3)
    at async Object.exports.handler (/Users/gozala/Projects/js-multiaddr/node_modules/mocha/lib/cli/run.js:366:5)
Command failed with exit code 1: mocha --ui bdd --timeout 5000 --unhandled-rejections=strict --colors --exit test/node.{js,ts} test/**/*.spec.{js,ts}

Not sure what is causing this one.

[Gozala]

I am starting to think that maybe *.ts files should only be included if --ts is passed. Otherwise a lot of problems just appear due to having .ts files in the repo without opting to even check them.