project setup

Udemy_ts_react $ npx create-react-app jbook --template typescript Udemy_ts_react $ cd jbook jbook $ npm install --save-exact [email protected] jbook $ npm start (this will start ts under watch mode AND start the server)

Syntax error: Could not find a declaration file for module 'react/jsx-runtime' solution: 'react' folder is missing in node_modules/@types/. So do this in project root: npm install @types/react. This will solve the problem.

SyntaxError: Unexpected token '<' solution: browser cache is cross contaminated. Close all of them if needed and restart. If Safari still has problem, go use Google Chrome.

Ref 197: ts not understanding immer's return data type The data store may be undefined, not always of CellState datatype. immer: return; -> could be undefined! That still does not solve the problem. Final solution: https://stackoverflow.com/questions/59511502/reducer-returned-undefined-during-initialization

cache: localForage in browser: inspect -> Storage -> indexed databases/filecache/keyvaluepairs -> check the cached libraries (the cache will not be available to other browser windows)

Ref 223: redux store should not store derived state. Orthogonal is highly recommended. selectors to access redux store: better synchronous, not async operations

Ref 237: animation by css instead of js progress bar

Ref 257: web service architecture

Ref 261: lerna setup $ sudo npm install -g --save-exact [email protected]