domProps set to null or undefined are set to '' on update.

[code-elf]

Version

2.6.8

Reproduction link

https://jsfiddle.net/bqzu8crg/

Steps to reproduce

Since this change, whenever an element updates which has one of its domProps set to undefined or null, that prop is instead set to ''.
All you need to do to reproduce it is render an element with properties in domProps set to null or undefined, and then update the component.

What is expected?

The domProps values retain their correct types.

What is actually happening?

The domProps become strings, instead.

[posva]

This is expected because a dom prop is casted by the browser into a string

[code-elf]

@posva What browser casts dom props into strings? They're not attributes and not expressed as such, and I've been using domProps to attach data to elements without issues across all browsers. There are, in fact, plenty of properties (not attributes!) on HTMLElement instances that are not strings. Please reopen this issue.

[Justineo]

It seems that now when domProps are updated, undefined and null will be converted to '' (empty string).

[posva]

Oh yeah, my bad was thinking about attributes

On Fri 8 Mar 2019 at 05:08, GU Yiling ***@***.***> wrote: It seems that now when domProps are updated, undefined and null will be converted to '' (empty string). — You are receiving this because you were mentioned. Reply to this email directly, view it on GitHub <#9650 (comment)>, or mute the thread <https://github.com/notifications/unsubscribe-auth/AAoicbZ9UM5-BAkCGv2pEOy7wFR4ijx9ks5vUeJagaJpZM4bkMxV> .

-- Eduardo San Martin Morote

[pistis]

@posva
@MayaWolf
I have tested this link in v2.6.9 with minor modifications.
(https://jsfiddle.net/pistis/5whnyt0q/6/)

When the x value of domProps is set to undefined
Test Scenario 1

1. Click the 'Click me' button
2. The value of document.getElementById('test').x is set to 'undefined'

Test Scenario 2

1. Click the 'Update' button
2. Click the 'Click me' button
3. The value of document.getElementById('test').x is 2 when this is done.

Also, if x value of domProps is set to null, the same result as above is displayed.

I estimate the following.

1. The value of the initial domProps is set correctly.
2. When DOM with domProps is updated via render, undefined and null are converted to empty string in vnode -> Real DOM conversion.