withSnackbar HOC re-rendering child unnecessarily

[martinmckenna]

Expected Behavior

in withSnackbar.js, there should be some sort of shallow props checking so that it ensures that it is not unnecessarily re-rendering it's child component. I suppose the shallow prop check would just check whether it already has access to the notistack props?

Current Behavior

Because of the lamda functions below, the child component is getting re-rendered with every single update because of the functions are getting reinstantiated, regardless of the child component already having access to the notistack props.

        {handlePresentSnackbar => (
            <SnackbarContextNext.Consumer>
                {handleEnqueueSnackbar => (
                    <Component
                        {...props}
                        onPresentSnackbar={handlePresentSnackbar}
                        enqueueSnackbar={handleEnqueueSnackbar}
                    />
                )}
            </SnackbarContextNext.Consumer>

Steps to Reproduce

Link:

It turns out this the bug that I found in my project wasn't actually caused by this, but I'm going to leave it open because having lamdas in render functions is inherently bad for performance and the above description still stands true.

[g-bastianelli]

I have similar problem. Children rerender when notification disappear.

[iamhosseindhv]

@g-bastianelli This will be fixed in the next release.

UPDATE:
this couldn't make it to v0.4.3 that I published today. So it'll be published in the next update next week.

[iamhosseindhv]

The reason for consumers re-rendering wasn't usage of lambda functions. React used to update consumers when value of SnackbarContext.Provider had changed, and this used to happen on every render because a new object for value prop was getting created.

Keeping reference to value object identical solved the issue.

Thanks everyone for your contribution.