For me this error is quite often when using axios. I can't setstate with undefined property. Eventhough i am getting actual response. I am pretty confused. Any solution would be appreciated.
json reply by axios reply
[ { main: 1,
left: 0,
right: 0,
top: 0,
bottom: 0,
cid: 6,
'$created': '2016-10-21T11:08:08.853Z',
'$updated': '2016-10-22T07:02:46.662Z',
stop: 0 } ]
code.js
import React from 'react';
import ReactDOM from 'react-dom';
import axios from 'axios';
export default class Main extends React.Component{
constructor(props){
super(props);
this.state = {
status:[]
}
}
componentDidMount(){
this.getdata()
}
getdata(){
axios.get('/getactions')
.then(function (data) {
console.log(data.data);
this.setState({
status:data
})
})
}
render(){
console.log(this.state)
return(
<div>
<button >Left</button>
</div>
)
}
}
ReactDOM.render(<Main/>,document.getElementBy
Id('app'))
this
within a standard function is usually determined by how it's called, not where the function was created. So this
in the callback function here is not the same as this
outside it:
getdata(){
axios.get('/getactions')
.then(function (data) {
console.log(data.data);
this.setState({
status:data
})
})
}
Arrow functions, however, close over the this
of their context, so:
getdata(){
axios.get('/getactions')
.then(data => { // <== Change is here
console.log(data.data);
this.setState({
status:data
})
})
}
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