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merged 4 commits into from
Oct 10, 2017
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added documentation for passing arguments to event handlers #81

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added documentation for passing arguments to event handlers
Oct 8, 2017
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modified handling-events page
Oct 10, 2017
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bvaughn Oct 10, 2017
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bvaughn Oct 10, 2017
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9 changes: 9 additions & 0 deletions content/docs/handling-events.md
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Expand Up @@ -139,3 +139,12 @@ class LoggingButton extends React.Component {
```

The problem with this syntax is that a different callback is created each time the `LoggingButton` renders. In most cases, this is fine. However, if this callback is passed as a prop to lower components, those components might do an extra re-rendering. We generally recommend binding in the constructor or using the class fields syntax, to avoid this sort of performance problem.

## Passing arguments to event handlers

Inside a loop it is common to want to pass a param to an event handler. For example, if `i` is the row id, either of the following would work:

```js
<button onClick={() => this.deleteRow(i)}>Delete Row</button>
<button onClick={this.deleteRow.bind(this, i)}>Delete Row</button>
```