## Description
This PR upgrades Prettier to v2 + enforces TypeScript’s [`import
type`](https://www.typescriptlang.org/docs/handbook/release-notes/typescript-3-8.html#type-only-imports-and-export)
syntax where applicable. It’s submitted as a separate PR so we can merge
it easily.
As a part of this PR, we reformat the codebase heavily:
- add `import type` everywhere where it’s required, and
- re-format the code to account for Prettier 2’s breaking changes:
https://prettier.io/blog/2020/03/21/2.0.0.html#breaking-changes
This PR is submitted against `release` to make sure all new code by team
members will adhere to new formatting standards, and we’ll have fewer
conflicts when merging `bundle-optimizations` into `release`. (I’ll
merge `release` back into `bundle-optimizations` once this PR is
merged.)
### Why is this needed?
This PR is needed because, for the Lodash optimization from
7cbb12af88,
we need to use `import type`. Otherwise, `babel-plugin-lodash` complains
that `LoDashStatic` is not a lodash function.
However, just using `import type` in the current codebase will give you
this:
<img width="962" alt="Screenshot 2023-03-08 at 17 45 59"
src="https://user-images.githubusercontent.com/2953267/223775744-407afa0c-e8b9-44a1-90f9-b879348da57f.png">
That’s because Prettier 1 can’t parse `import type` at all. To parse it,
we need to upgrade to Prettier 2.
### Why enforce `import type`?
Apart from just enabling `import type` support, this PR enforces
specifying `import type` everywhere it’s needed. (Developers will get
immediate TypeScript and ESLint errors when they forget to do so.)
I’m doing this because I believe `import type` improves DX and makes
refactorings easier.
Let’s say you had a few imports like below. Can you tell which of these
imports will increase the bundle size? (Tip: it’s not all of them!)
```ts
// app/client/src/workers/Linting/utils.ts
import { Position } from "codemirror";
import { LintError as JSHintError, LintOptions } from "jshint";
import { get, isEmpty, isNumber, keys, last, set } from "lodash";
```
It’s pretty hard, right?
What about now?
```ts
// app/client/src/workers/Linting/utils.ts
import type { Position } from "codemirror";
import type { LintError as JSHintError, LintOptions } from "jshint";
import { get, isEmpty, isNumber, keys, last, set } from "lodash";
```
Now, it’s clear that only `lodash` will be bundled.
This helps developers to see which imports are problematic, but it
_also_ helps with refactorings. Now, if you want to see where
`codemirror` is bundled, you can just grep for `import \{.*\} from
"codemirror"` – and you won’t get any type-only imports.
This also helps (some) bundlers. Upon transpiling, TypeScript erases
type-only imports completely. In some environment (not ours), this makes
the bundle smaller, as the bundler doesn’t need to bundle type-only
imports anymore.
## Type of change
- Chore (housekeeping or task changes that don't impact user perception)
## How Has This Been Tested?
This was tested to not break the build.
### Test Plan
> Add Testsmith test cases links that relate to this PR
### Issues raised during DP testing
> Link issues raised during DP testing for better visiblity and tracking
(copy link from comments dropped on this PR)
## Checklist:
### Dev activity
- [x] My code follows the style guidelines of this project
- [ ] I have performed a self-review of my own code
- [ ] I have commented my code, particularly in hard-to-understand areas
- [ ] I have made corresponding changes to the documentation
- [x] My changes generate no new warnings
- [ ] I have added tests that prove my fix is effective or that my
feature works
- [ ] New and existing unit tests pass locally with my changes
- [ ] PR is being merged under a feature flag
### QA activity:
- [ ] Test plan has been approved by relevant developers
- [ ] Test plan has been peer reviewed by QA
- [ ] Cypress test cases have been added and approved by either SDET or
manual QA
- [ ] Organized project review call with relevant stakeholders after
Round 1/2 of QA
- [ ] Added Test Plan Approved label after reveiwing all Cypress test
---------
Co-authored-by: Satish Gandham <hello@satishgandham.com>
Co-authored-by: Satish Gandham <satish.iitg@gmail.com>
