This isn't working because "this" is different inside of axios. "this" inside axios refers to the axios object, not your react component. You can resolve this with .bind
var self= this; // self will now be referred to your component
axios.get("http://localhost:3001/get_user?id=" + id)
.then(function (response) {
if(response.data.rows != null)
user_detail = response.data.rows;
console.log(response);
self.setState({email: user_detail.name, name: user_detail.name})
})
I have dealt with promises similar to that in the past when I was learning react. What I did was put the api call on the componentDidMount method and set the state to an initial value. I used a loader while the data was being fetched.
You have a syntax error here. You should try this instead
var self = this;
axios.get('/url')
.then(function (response) {
console.log(response);
self.setState({events: response.data})
})
.catch(function (error) {
console.log(error);
});
//the rest of the code
var a = 'i might be executed before the server responds'
There are a few things to note here:
axios.get is an asynchronous function which means that the rest of the code will be executed .And when the response of the server arrives, the function passed to then will be executed. The return value of axios.get('url') is called a promise object. You can read more about it here
this keyword has a different value depending of where it is called. this in this.setStateshould refer to the constructor object, and when you call this inside a function, it refers to the window object. That is why i assigned this to the variable self. You can read more about this here
Pro tip:
If you use ES6, you would want to use arrow functions (which don't have their own this) and use this.setState without assigning this to a variable. more about it here
Here is a complete example https://codesandbox.io/s/rm4pyq9m0o containing best practices commonly used to fetch data including error handling, try again and loading. This provides a better User experience. You are encouraged to modify the code and play around to get more insights about it.
This isn't working because "this" is different inside of axios. "this" inside axios refers to the axios object, not your react component. You can resolve this with .bind
Also axios isnt being used properly.
it should look something like
Alternatively if using es6 you could sub out the function for an arrow function and get the same effect without bind
Do something like this:
I have dealt with promises similar to that in the past when I was learning react. What I did was put the api call on the
componentDidMount
method and set the state to an initial value. I used a loader while the data was being fetched.As of now, I would use something similar to what checkenrode said.
You have a syntax error here. You should try this instead
There are a few things to note here:
axios.get
is an asynchronous function which means that the rest of the code will be executed .And when the response of the server arrives, the function passed tothen
will be executed. The return value ofaxios.get('url')
is called a promise object. You can read more about it herethis
keyword has a different value depending of where it is called.this
inthis.setState
should refer to the constructor object, and when you callthis
inside a function, it refers to thewindow
object. That is why i assignedthis
to the variableself
. You can read more about this herePro tip:
If you use ES6, you would want to use arrow functions (which don't have their own
this
) and usethis.setState
without assigningthis
to a variable. more about it hereHere is a complete example https://codesandbox.io/s/rm4pyq9m0o containing best practices commonly used to fetch data including error handling, try again and loading. This provides a better User experience. You are encouraged to modify the code and play around to get more insights about it.
Simply try this node js
if you are using react js then you first import in component than use axios
like this: