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Added explicit null value in state initializer

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This commit is contained in:
Brian Vaughn
2018-03-15 08:48:01 -07:00
parent 3c75def7e7
commit 55650fc12c
1 changed files with 3 additions and 2 deletions
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5
examples/update-on-async-rendering/updating-state-from-props-after.js
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@@ -2,18 +2,19 @@
class ExampleComponent extends React.Component {
// Initialize state in constructor,
// Or with a property initializer.
// highlight-range{1-3}
// highlight-range{1-4}
state = {
isScrollingDown: false,
lastRow: null,
};
// highlight-line
// highlight-range{1-8}
static getDerivedStateFromProps(nextProps, prevState) {
if (nextProps.currentRow !== prevState.lastRow) {
return {
lastRow: nextProps.currentRow,
isScrollingDown:
nextProps.currentRow > prevState.lastRow,
lastRow: nextProps.currentRow,
};
}