Prepare for concurrently developing in TS and Flow

[JacksonKearl]

• Move .d.ts files from ./tstypes into ./src
• Add tsconfigs to ./ for both building and type checking the project
• Modify resources/build.js to work with .ts and .d.ts files
• Add TS build scripts to ./package.json
• Convert jsutils/dedent.js to jsutils/dedent.ts and jsutils/dedent.js.flow as an example of conversion proccess
• Convert jsutils/__tests__/dedent-test.js to jsutils/__tests__/dedent-test.ts as an example of conversion proccess

[IvanGoncharov]

Since we will ship .d.ts alongside of .js files, why do we need this?

[JacksonKearl]

TS docs say its good practice:

Also note that if your main declaration file is named index.d.ts and lives at the root of the package (next to index.js) you do not need to mark the "types" property, though it is advisable to do so.

https://www.typescriptlang.org/docs/handbook/declaration-files/publishing.html

What do you think?

[IvanGoncharov]

@JacksonKearl Thanks for link now it make sense.
Can you please create PR against master?

[IvanGoncharov]

Please extract all changes in .d.ts into PR against master.
Please keep d.ts files in sync with flow files:

graphql-js/src/language/lexer.js

Line 5 in 85d4c99

import { syntaxError } from '../error/syntaxError';

Also, we never use index files inside the library only direct imports from files.

[JacksonKearl]

Got it, up at #2140

[IvanGoncharov]

@JacksonKearl Looks great 👍
Also I need to look into tsc compiler before I can review build.js part and tsconfig files.

After we stabilize 14.5.x I want to release 15.0.0-alpha.1 with all expected breaking changes (but without TS conversion) so Apollo, Facebook, GraphiQL, Nexus, typed-graphql, and other big API clients can test it locally and give early feedback on proposed breaking changes. Plus we would have it as baseline quickly check if the particular issue was added during TS conversion or existed before.

Also, I need to be able to rebase 15.x.x on top of master until we fully stabilize 14.5.x a line.
So if everything goes smooth we can merge it around Monday.

[JacksonKearl]

Alright, I'll be out of a job starting Friday so definitely let me know if there's anything I can do before then. I'll put up a PR against master with the .d.ts and package lock changes today

[IvanGoncharov]

@JacksonKearl After I merge your .d.ts changes into master I will release 14.5.4 and would be extremely useful if you migrate as many Apollo projects as possible to use this version (or at least try it locally).

[IvanGoncharov]

@JacksonKearl Also can you please try that code coverage is working with TS files?

[IvanGoncharov]

@JacksonKearl Would be great if can try all NPM scripts and ensure that they are working with TS files. For example, will ESLint validate TS files?
Also can we get TS-specific rules from https://github.com/typescript-eslint/typescript-eslint

[JacksonKearl]

@IvanGoncharov Added support for code coverage checking in TS files

[JacksonKearl]

Do we have a 14.5.4 cut yet?

[JacksonKearl]

Will look into the scripts today

[JacksonKearl]

Got ES lint to lint the typescript files, and using the recommended rules from https://github.com/typescript-eslint/typescript-eslint

[IvanGoncharov]

Do we have a 14.5.4 cut yet?

Sorry for the delay, published 14.5.4 📦