[NO JIRA] add 'hasChildrenOfType' to bpk-react-utils

[janeklb]

Currently lives in bpk-component-datatable (added here: bf00596) but makes sense to move to bpk-react-utils.

This PR is just to add the functionality to bpk-react-utils, then will submit a separate one for bpk-component-datatable.

[backpackbot]

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[k0nserv]

Can we explain how this is different to PropTypes.instanceOf? That was my first question upon seeing this.

[janeklb]

Would adding 'Component' help? Totally open to suggestions if you have any ideas.
eg.

A prop type checker that allows you to restrict a component's children to a specific (Component) type.

[matthewdavidson]

@janeklb I second @k0nserv's question, what's the difference between using hasChildrenOfType(MyComponent) & PropTypes.instanceOf(MyComponent)? I.e. i think we are questioning whether this new prop type is redundant or not.

[janeklb]

PropTypes.instanceOf(...) uses js's instanceof operator to see if the prop value is an instance of the supplied class/type. It doesn't work with components (ie. jsx or React.createElement etc.) since those can't be operated on with instanceof.

This type checker validates that the children of a component are all "instances" of a certain component.

[janeklb]

See the tests - they should give some more clarity :)

[janeklb]

tbh im not sure why this isn't a part of prop-types itself -- seems like a common enough requirement

update: looks like it may be soon.. facebook/prop-types#146

[janeklb]

And airbnb's prop types seem to already support something like this https://www.npmjs.com/package/airbnb-prop-types

[matthewdavidson]

@janeklb where do you see this being used in backpack? Im tempted to close this as it can safely exist in userland and will most likely be available in prop-types at some point as you point out.

[janeklb]

@matthewdavidson This is being used in bpk-component-datatable :)

It was inspired by react-virtualized's Table children validator

[matthewdavidson]

@janeklb Lets keep it inlined within the data table component package then dude - we don't think bpk-react-utils is necessarily the best place for it. We can revisit it as per rule of three if the times comes - hopefully it'll be in prop-types by then.

[janeklb]

sounds good! cheers