Failed to build extension code with "shopify extension push"

shopify extension push returns the following

Failed to build extension code.
┏━━ Building extension with: npm… ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━
┃
┃ > product-reviews-sample-checkout-extension@0.1.0 build
┃ > checkout-ui-extensions-run build
┃
┃ sh: checkout-ui-extensions-run: command not found
┗━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━

What’s funny is that it did create checkout extension albeit the error.

[ratapof]

Fixed for me, by running npm install in the checkout app extension folder. This was not specified in the README.md and should be in my opinion.

[tommy921092]

I found this from the Theme app extensions overview docs helpful

Theme app extensions are currently available in a developer preview and can only be used in development stores.

For the add section or add block in the theme editor, on development stores, in the extension settings I had to set DEVELOPMENT STORE PREVIEW to enabled in order for it to show on my theme (Dawn)

I had my DEVELOPMENT STORE PREVIEW enabled but still its not showing on my theme. the theme app extension and checkout extension is already pushed and published. This is online store dawn theme. Any ideas?

Finally notice that it has to be enabled in theme editor, or via deep linking https://www.youtube.com/watch?v=xYz_XMY7jEU&t=259s