addon-knobs | Select | Knobs after select disappear when you pass to select an object with empty string key as options

[nekitk]

Describe the bug
When you pass to select's options an object with an empty string as a key select itself renders and works properly, but all the knobs after the select fail to render.

Using 0, null or undefined as a key doesn't affect rendering, only empty string.

To Reproduce
Steps to reproduce the behavior:

1. Edit examples/official-storybook/stories/addon-knobs.stories.js
2. Add '': '', option to fruits
3. Open storybook
4. Knobs after select doesn't appear (see screenshot below)

Expected behavior
All knobs should be rendered

Screenshots

Code snippets

const fruits = {
  '': '',
  Apple: 'apple',
  Banana: 'banana',
  Cherry: 'cherry',
};
const fruit = select('Fruit', fruits, 'apple');

System:

Environment Info:

  System:
    OS: macOS High Sierra 10.13.6
    CPU: (4) x64 Intel(R) Core(TM) i3-4370 CPU @ 3.80GHz
  Binaries:
    Node: 10.16.0 - /usr/local/bin/node
    Yarn: 1.17.3 - ~/.yarn/bin/yarn
    npm: 6.10.2 - /usr/local/bin/npm
  Browsers:
    Chrome: 76.0.3809.100
    Firefox: 55.0.3
    Safari: 12.1.2

Additional context
Discovered in storybook-eol/addon-smart-knobs#59

[stale]

Hi everyone! Seems like there hasn't been much going on in this issue lately. If there are still questions, comments, or bugs, please feel free to continue the discussion. Unfortunately, we don't have time to get to every issue. We are always open to contributions so please send us a pull request if you would like to help. Inactive issues will be closed after 30 days. Thanks!

[stale]

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!