Trying typescript monobuild and last step fails following simple blog article

Question

My yarn -v yield v1.22.15

The steps for reproducing the error below are pretty simple.

• git clone [email protected]:ahoopen/typescript-mono-repo.git
• cd typescript-mono-repo
• yarn install
• yarn build

Failure ->

dean@Deans-MBP typescript-mono-repo % yarn build
yarn run v1.22.15
$ lerna run build --stream
lerna notice cli v3.22.1
lerna info versioning independent
lerna info Executing command in 3 packages: "yarn run build"
@ahoopen/core: $ yarn clean && tsc --build && cp "./package.json" ./dist/
@ahoopen/utils: $ yarn clean && tsc --build && cp "./package.json" ./dist/
@ahoopen/core: $ rimraf dist && rimraf tsconfig.tsbuildinfo
@ahoopen/utils: $ rimraf dist && rimraf tsconfig.tsbuildinfo
@ahoopen/web: $ yarn clean && tsc --build && cp "./package.json" ./dist/
@ahoopen/web: $ rimraf dist && rimraf tsconfig.tsbuildinfo
@ahoopen/web: src/add.ts(1,31): error TS2307: Cannot find module '@ahoopen/utils' or its corresponding type declarations.
@ahoopen/web: error Command failed with exit code 1.
@ahoopen/web: info Visit https://yarnpkg.com/en/docs/cli/run for documentation about this command.
lerna ERR! yarn run build exited 1 in '@ahoopen/web'
error Command failed with exit code 1.
info Visit https://yarnpkg.com/en/docs/cli/run for documentation about this command.
dean@Deans-MBP typescript-mono-repo %

Any idea what I can do to make this work?. I am pretty new to typescript & yarn workspaces (ie. very new).