Add eslint

[Ethan-Arrowood]

✨ Wonderful Project! Thought i could lend a hand and add eslint for you. The configuration I'm using is based on one I'm using in my own TypeScript package development project: Matterhorn. Going to push a second commit that adds rules to fit the current project structure. Furthermore, I set the ecmaVersion based on what you have in the tsconfig.json file. Let me know if you have any questions!

[Ethan-Arrowood]

Looks like there may be a conflict with prettier. I'll defer to your review on what modifications I should make. I believe there is a plugin to merge prettier with eslint I just haven't used it in a while

[jaredpalmer]

Do a reinstall with yarn for me.

[jaredpalmer]

and push

[jaredpalmer]

We've been a little lazy to move off of TSLint on our team. I guess we should bite the bullet and update palmerhq/typerscript.

[Ethan-Arrowood]

This PR actually inspired me to dive head first and write up a detailed article on TypeScript + ESLint. You can check out the unpublished version here. It is nearly done just waiting on one more peer to review it. In the article I detail how to set it up with prettier too. I'm going to push some changes to this PR soon with an ESLint & Prettier integration (also outlined in the article).

[Ethan-Arrowood]

Okay updated and fixed up some of the rules. Pretty close to passing. Here is the current output of yarn lint

👻 tsdx (add-eslint)▷ yarn lint
yarn run v1.15.2
$ eslint src/**/*.ts

/Users/ethanarrowood/Documents/GitHub/tsdx/src/createJestConfig.ts
  1:8  warning  'fs' is defined but never used    @typescript-eslint/no-unused-vars
  2:8  warning  'path' is defined but never used  @typescript-eslint/no-unused-vars

/Users/ethanarrowood/Documents/GitHub/tsdx/src/createRollupConfig.ts
  2:1  error  'ge' is not defined  no-undef

/Users/ethanarrowood/Documents/GitHub/tsdx/src/index.ts
   25:13  error    Require statement not part of import statement  @typescript-eslint/no-var-requires
   26:22  error    Require statement not part of import statement  @typescript-eslint/no-var-requires
   38:10  warning  Unexpected any. Specify a different type        @typescript-eslint/no-explicit-any
   42:13  warning  Empty block statement                           no-empty
   60:1   error    Expected indentation of 6 spaces but found 4    @typescript-eslint/indent
   61:1   error    Expected indentation of 6 spaces but found 4    @typescript-eslint/indent
   67:15  warning  Unexpected any. Specify a different type        @typescript-eslint/no-explicit-any
   68:13  warning  Unexpected any. Specify a different type        @typescript-eslint/no-explicit-any
   81:35  warning  Unexpected any. Specify a different type        @typescript-eslint/no-explicit-any
  105:15  warning  Empty block statement                           no-empty
  225:7   warning  Unexpected console statement                    no-console
  244:24  warning  Unexpected any. Specify a different type        @typescript-eslint/no-explicit-any
  257:1   error    Expected indentation of 4 spaces but found 10   @typescript-eslint/indent
  258:1   error    Expected indentation of 2 spaces but found 8    @typescript-eslint/indent
  261:1   error    Expected indentation of 4 spaces but found 10   @typescript-eslint/indent
  262:1   error    Expected indentation of 2 spaces but found 8    @typescript-eslint/indent
  291:9   warning  Unexpected console statement                    no-console
  296:26  warning  Empty block statement                           no-empty
  312:24  warning  Unexpected any. Specify a different type        @typescript-eslint/no-explicit-any
  327:1   error    Expected indentation of 4 spaces but found 10   @typescript-eslint/indent
  328:1   error    Expected indentation of 2 spaces but found 8    @typescript-eslint/indent
  331:1   error    Expected indentation of 4 spaces but found 10   @typescript-eslint/indent
  332:1   error    Expected indentation of 2 spaces but found 8    @typescript-eslint/indent
  353:20  warning  Unexpected any. Specify a different type        @typescript-eslint/no-explicit-any

/Users/ethanarrowood/Documents/GitHub/tsdx/src/logError.ts
  3:16  warning  Unexpected console statement              no-console
  5:39  warning  Unexpected any. Specify a different type  @typescript-eslint/no-explicit-any

/Users/ethanarrowood/Documents/GitHub/tsdx/src/output.ts
   7:3  warning  Unexpected console statement  no-console
  15:3  warning  Unexpected console statement  no-console
  19:3  warning  Unexpected console statement  no-console

✖ 32 problems (13 errors, 19 warnings)
  10 errors and 0 warnings potentially fixable with the `--fix` option.

error Command failed with exit code 1.
info Visit https://yarnpkg.com/en/docs/cli/run for documentation about this command.

[skvale]

Configuring eslint with TypeScript isn't easy. What if tsdx had a lint command as well? #99

And it used tsdx lint to lint its own source code.

[jaredpalmer]

See #99

[twmulloy]

wut.