Unable to access React instance (this) inside event handler?

Answer • 1 Asked • Mar 16 2019
I am writing a simple component in ES6 (with BabelJS), and functions this.setState is not working.

Typical errors include something like
Cannot read property 'setState' of undefined

or
this.setState is not a function

Do you know why? Here is the code:
import React from 'react' class SomeClass extends React.Component { constructor(props) { super(props) this.state = {inputContent: 'startValue'} } sendContent(e) { console.log('sending input content '+React.findDOMNode(React.refs.someref).value) } changeContent(e) { this.setState({inputContent: e.target.value}) } render() { return ( <div> <h4>The input form is here:</h4> Title: <input
type="text"
ref="someref" value={this.inputContent} onChange={this.changeContent}
/> <button onClick={this.sendContent}>Submit</button> </div> ) } } export default SomeClass

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