Moving to TypeScript

[ovr]

Hey!

In 2020 TypeScript started to be a standard (exclude flow in fb internals 😄 ) for every project, It helps use to:

• Speedup development (autocompletion, easy to know how to implement drivers by interfaces/abstract classes)
• Protect errors
• Generate true compatibility code for matrix of compatibility versions of Node.JS platform

Before We start

1. Performance should not be affected
2. BC should be done as deprecated notice, next code removal
3. Dont break exists typings if they provided (merge to interfaces?)

High level iteration plan:

Scope

Due to the fact, that cube.js is not a small project, it's expected to have a plan, How to move it to TypeScript.

It's not possible to move module with dependency on another module that doesn't have typings. It's why dependency tree is useful to detect "core" modules.

Guide

1. Generate declarations for every package automatically (1-2 base packages, it's needed to write driver on TypeScript)
2. Introduce first driver fully on top of TS
3. Move packages from 1st step to TS
4. Move all packages to TS

Scope

Isolated packages

• [x] cubejs-cli

Frontend packages

• [ ] cubejs-client-core
• [x] cubejs-client-ngx
• [ ] cubejs-client-react
• [ ] cubejs-client-vue
• [x] cubejs-client-ws-transport (https://github.com/cube-js/cube.js/pull/1293)

Backend packages (base only)

• [x] cubejs-api-gateway (https://github.com/cube-js/cube.js/pull/1474)
• [X] cubejs-query-orchestrator (https://github.com/cube-js/cube.js/pull/1092)
• [x] cubejs-schema-compiler
• [x] cubejs-server-core
• [X] cubejs-server
• [ ] cubejs-serverless
• [ ] cubejs-serverless-aws
• [ ] cubejs-serverless-google

Drivers

• [x] cubejs-athena-driver
• [x] cubejs-bigquery-driver (https://github.com/cube-js/cube.js/pull/2818)
• [x] cubejs-cubestore-driver
• [ ] cubejs-dremio-driver
• [x] cubejs-druid-driver (new one, fully on TS) (https://github.com/cube-js/cube.js/pull/1099)
• [ ] cubejs-elasticsearch-driver
• [ ] cubejs-hive-driver
• [x] cubejs-jdbc-driver (blocked, fully outdated)
• [x] cubejs-mongobi-driver
• [ ] cubejs-mssql-driver
• [x] cubejs-mysql-driver
• [ ] cubejs-oracle-driver
• [x] cubejs-postgres-driver
• [x] cubejs-prestodb-driver
• [ ] cubejs-sqlite-driver
• [X] cubejs-snowflake-driver

Non code

• [x] ESLint (support typescript)
• [ ] Docs (a little bit of examples, how to debug?)
• [ ] Tests

Thanks

[vincentwinkel]

Hello, Small issue here when I build using tsc:

    "@typescript-eslint/eslint-plugin": "^3.8.0",
    "@typescript-eslint/parser": "^3.8.0",
    "cross-env": "^7.0.2",
    "ts-node-dev": "^1.1.8",
    "tsconfig-paths": "^3.9.0",
    "type-graphql": "^1.0.0-rc.3",
    "typescript": "^3.9.7",
    "@cubejs-backend/postgres-driver": "^0.28.46",
    "@cubejs-backend/server-core": "^0.28.46"

[reify-thomas-smith]

I've taken a few stabs at converting both cubejs-client-core and cubejs-client-react. This is what I've learned:

• The Rollup config doesn't correctly handle file extensions other than .js. (This didn't cause problems for cubejs-client-ws-transport because it doesn't import any .ts files.) PR #4541 would fix this, as well as a number of build warnings.
• The Rollup config processes TypeScript files by running them through @babel/preset-typescript. I think that this would not catch type errors. Probably we should use e.g. @rollup/plugin-typescript to transpile TypeScript instead of using Babel.
• The TypeDoc scripts currently only look at index.d.ts files. These scripts would presumably need to be modified.
• In addition, if TypeDoc uses the declared types, then it's possible that when we use more detailed types, some tweaking might be necessary to keep the output readable.
• The tests for cubejs-client-core are run directly on the source code, not on the compiled bundle. The test config would probably need an update to support TypeScript. The same is likely true of other packages with tests.