Major refactoring using ESLint with rules from AirBnb and Vue.
Enable most of the ESLint rules and do necessary linting in the code.
Also add more information for rules that are disabled to describe what
they are and why they are disabled.
Allow logging (`console.log`) in test files, and in development mode
(e.g. when working with `npm run serve`), but disable it when
environment is production (as pre-configured by Vue). Also add flag
(`--mode production`) in `lint:eslint` command so production linting is
executed earlier in lifecycle.
Disable rules that requires a separate work. Such as ESLint rules that
are broken in TypeScript: no-useless-constructor (eslint/eslint#14118)
and no-shadow (eslint/eslint#13014).
TSLint deprecated and is being replaced by ESLint.
Add Vue CLI plugin (@vue/cli-plugin-eslint) using:
`vue add @vue/cli-plugin-eslint`. It also adds `.eslintrc.js` manually
for Cypress since Vue CLI for ESLint misses it (vuejs/vue-cli#6892).
Also rename `npm run lint:vue` to `npm run lint:eslint` for better
clarification.
This commit disables all rules that the current code is not compliant
with. This allows for enabling them gradually and separating commits
instead of mixing ESLint introduction with other code changes.
AirBnb is chosen as base configuration.
"Standard" is not chosen due to its poor defaults. It makes code cleaner
but harder to maintain:
- It converts interfaces to types which is harder to read.
- Removes semicolons that helps to eliminate some ambigious code.
"Airbnb" on the other hand helps for easier future changes and
maintinability:
- Includes more useful rules.
- Keeps the semicolons and interfaces.
- Enforces trailing commas that makes it easier to delete lines later on.
- Delete branches: standard, prettier.
Alias would remove unnecessary repetitions and less relative paths make changes easier when moving around files. This commit cleans also up some relative paths ('../../../') by using the alias and orders imports. It updates both path alias in tsconfig and module alias in Vue CLI's bundler (vuejs/vue-cli#2398).
