Fluentui: Dropdown selectedKey and defaultSelectedKey behavior

[aboryczko]

I have a question about the behavior of defaultSelectedKey and selectedKey on the Dropdown component. Currently defaultSelectedKey overrides selectedKey when the component renders for the first time. As I understand usually when a value is null/undefined we can specify some other value as the default, but this behavior contradicts this logic. Is this correct?

[cschleiden]

You want to use selectedKey if it's a controlled component, and typically defaultSelectedKey if it's an uncontrolled component. The behavior should be similar to
https://facebook.github.io/react/docs/forms.html and https://facebook.github.io/react/docs/uncontrolled-components.html#default-values

[dzearing]

@cschleiden One thing we should consider is to refine how deprecation warnings occur. Right now BaseComponent takes in a deprecation map. However I think this is the wrong design. Instead I was thinking we'd have a deprecation.ts file that exposes helpers for generating warnings.

This file could export a variety of helpers to deprecate specific scenarios:

warnDeprecatedMap(props, { map });
warnDeprecatedEnum(props.enum, [ Enum.val1, Enum.val2 ]);
warnMutuallyExclusive(props, 'selectedKey', 'defaultSelectedKey');

In this particular case we should warn that these two things are mutually exclusive.

[cschleiden]

@dzearing that makes sense, and maybe only do it in non-production mode.

[dzearing]

@cschleiden Made a PR for it. however, it's more of a webpack configuration deal to strip in production mode. I think we should, but not sure the best way.

[cschleiden]

Great. On vacation right now, if still open on Monday I'll take a look :)

For conditional compilation I've used https://github.com/nippur72/ifdef-loader/blob/master/README.md for another project, but not sure if stable enough for office fabric.

On Apr 1, 2017 15:57, David Zearing [e-mail] wrote:

@cschleidenhttps://github.com/cschleiden Made a PR for it. however, it's more of a webpack configuration deal to strip in production mode. I think we should, but not sure the best way.

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