Warn for Context.Consumer with contextType #14831
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gaearon
reviewed
Feb 12, 2019
| if (contextType.$$typeof !== REACT_CONTEXT_TYPE) { | ||
| const isContextConsumer = | ||
| contextType.$$typeof === REACT_CONTEXT_TYPE && | ||
| contextType._context !== undefined; |
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Was it also called context in some patch release?
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Yeah, it was changed to _context in #12501. Is it worth checking? I think a lot more would be broken if you were trying to render a tree created with a version of React that still used context since we don't check for it in the context code paths.
matthargett
approved these changes
Feb 13, 2019
gaearon
reviewed
Mar 18, 2019
| @@ -515,17 +515,21 @@ function constructClassInstance( | |||
| const contextType = ctor.contextType; | |||
| if (typeof contextType === 'object' && contextType !== null) { | |||
| if (__DEV__) { | |||
| const isContextConsumer = | |||
| contextType.$$typeof === REACT_CONTEXT_TYPE && | |||
| contextType._context !== undefined; | |||
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What if context value actually is undefined?
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Isn't the context value tracked as _currentValue on this _context element?
gaearon
approved these changes
Mar 18, 2019
gaearon
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Mar 27, 2019
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Fixes #14793
Extends the
contextTypewarning to includeContext.Consumer. For both theReactDOMandReactDomServer.Since
$$typeofalone can't be used to distinguish consumers from context objects, the heuristic I used to identify context consumers was to check for the_contextproperty which doesn't exist on the context object itself.