[BUG] Persistence does not work for Input components when 0 is entered

[josephandreas]

Hi all,

Apologies for crude formatting below, never used GitHub before.

Persistence does not work for Input types when 0 is entered.

Minimal example:
app.layout = html.Div([ dcc.Input(type='number', id='test', persistence_type='local', persistence=True) ])
Enter a number 1 in the browser and reenter 0. Refresh the browser.
Expected value in Input: 0
Given value: 1

Possible duplicates: #1034
Possible solution (at least it works in my desktop):
change
forEach(persistedProp => { const [propName, propPart] = persistedProp.split('.'); if (newProps[propName]) {

to
forEach(persistedProp => { const [propName, propPart] = persistedProp.split('.'); if (newProps[propName] !== undefined) {

[eddy-geek]

for completeness, I think this is the line @josephandreas is mentioning: persistence.js#L320

I've been able to "patch" a dev server with:

sed -i 's/if (newProps\[propName\])/if (newProps[propName] !== undefined)/g' <your_python_env>/lib/python3.6/site-packages/dash_renderer/dash_renderer.dev.js

[alexcjohnson]

Thanks @eddy-geek for the fix in #1142 🎉