Web3 1.2.9

breaks the wallet.keystore decryption in React because of some effect after switching from @web3-js/scrypt-shim to scrypt-js: https://github.com/ethereum/web3.js/compare/v1.2.8...v1.2.9#diff-7bb2a20126193b9ecfe4723f83429c49L33

that seems to be a side effect of node_modules/node-libs-browser/node_modules/buffer/index.js:399 that explicity checks that a Buffer is a Buffer and not an

error message is
TypeError: "list" argument must be an Array of Buffers

try it

yarn
yarn remove web3
yarn add web3@1.2.8
yarn run start #works;
yarn remove web3
yarn add web3@1.2.9
yarn run start #breaks;
yarn remove web3
(npm i -g lerna)
yarn add web3@https://github.com/ethereum/web3.js.git#1.x
yarn run start #works

see it works on 1.2.8

change web3 dependency to 1.2.8 in package.json and run again

doesn't happen in plain JS:

cp node_modules/web3/dist/web3.min.js public/web3.min.js
yarn build
serve -s build
http://localhost:3000/plain.html #works

fixed in web3.js

https://github.com/ethereum/web3.js/commit/d6bdafd73be901bd280d17d4126d25ffa23da556 web3/web3.js#3580