Knobs numbers return null instead of undefined

Describe the bug I know somebody would say that this is not an error, but knobs ‘number’ dont work with default parameter values because it returns null instead of undefined on empty string.

To Reproduce

1. Create a React/Angular component with default value and write a story for it.
2. When you delete all context from the knobs input in storybook the value in the component will be null instead of the default value. (And this is because default values only works with undefined and not null)

Expected behavior expect undefined, not null

Code snippets storybook/addons/knobs/src/converters.js Line 18:

  toFloat: value => (value === '' ? null : parseFloat(value)),

Should be:

  toFloat: value => (value === '' ? undefined : parseFloat(value)),

bs and good in general 😃

[alfnielsen]

I dont believe it’s a duplicate of #4487 but clearly related.

The problem with ‘select’ knobs require another solution then this does.

The ‘number’ knobs is because it’s has been choosen at some point to return ‘null’ in storybook/addons/knobs/src/converters.js for numbers that a empty string instead of undefined

[stale[bot]]

Hey there, it’s me again! I am going close this issue to help our maintainers focus on the current development roadmap instead. If the issue mentioned is still a concern, please open a new ticket and mention this old one. Cheers and thanks for using Storybook!