Error when trying to edit a slice via Slice Builder UI

Version

• Prismic CLI version (know it by running prismic --version): 3.8.8

Reproduction

1. Run Slice Builder using prismic sm --develop

2. Open Slice Builder at http://localhost:9999/ and access my first created slice (via prismic sm --create-slice)

3. Add a new field and click on Save model to filesystem

What is expected?

I expect new field to be saved

What is actually happening?

Feld is not being saved and error appears in terminal:

[slice-machine] [update]: generating mocks

[slice-machine] (node:49124) UnhandledPromiseRejectionWarning: TypeError: content.flat is not a function
    at createMockFromConfig (/Users/pablo/jamstack/peanutbutter-site/node_modules/slice-machine-ui/lib/widgets/StructuredText/Mock/index.js:75:18)
    at handleMockConfig (/Users/pablo/jamstack/peanutbutter-site/node_modules/slice-machine-ui/lib/widgets/StructuredText/Mock/index.js:83:10)
    at handleFieldMock (/Users/pablo/jamstack/peanutbutter-site/node_modules/slice-machine-ui/lib/mock/handlers.js:23:12)
    at fields.reduce (/Users/pablo/jamstack/peanutbutter-site/node_modules/slice-machine-ui/lib/mock/handlers.js:41:20)
    at Array.reduce (<anonymous>)
    at /Users/pablo/jamstack/peanutbutter-site/node_modules/slice-machine-ui/lib/mock/handlers.js:36:17
    at model.variations.map.variation (/Users/pablo/jamstack/peanutbutter-site/node_modules/slice-machine-ui/lib/mock/index.js:15:20)
    at Array.map (<anonymous>)
    at default (/Users/pablo/jamstack/peanutbutter-site/node_modules/slice-machine-ui/lib/mock/index.js:12:39)
    at handler (/Users/pablo/jamstack/peanutbutter-site/node_modules/slice-machine-ui/server/api/update.js:77:29)

[slice-machine] (node:49124) UnhandledPromiseRejectionWarning: Unhandled promise rejection. This error originated either by throwing inside of an async function without a catch block, or by rejecting a promise which was not handled with .catch(). (rejection id: 2)
(node:49124) [DEP0018] DeprecationWarning: Unhandled promise rejections are deprecated. In the future, promise rejections that are not handled will terminate the Node.js process with a non-zero exit code.

Any additional information

If I access my storybook for this slice I see this error:

[pablogiralt]

thanks @lihbr! closing this

[lihbr]

Oh great! Glad you figured it out~

Indeed Slice Machine requires v12 now at least, we’ll have some warning enforcing that pretty soon 🙂