Hi I have this function (apiCall) that calls an API inside a component and uses the data to update state (to then render a chart with chartjs). I want to test specifically the process inside componentDidMount that updates state without calling the API. After lots of time spent searching for a way of mocking this I still haven't been able to figure it out. Trying to assert the changed state from a mock apiCall function.
this is the apiCall function:
const apiCall = (uri) => {
return fetch(uri)
.then( (res) => {
return res
})
.catch( (ex) => {
return 0
})
}
export default apiCall;
// and this is the componentDidMount
componentDidMount() {
apiCall(this.props.uri)
.then((result) => result.json())
.then((result) => {
this.setState({ data: result });
})
this.setState({ legend: this.props.legend })
}
One of the options is to use fetch-mock
http://www.wheresrhys.co.uk/fetch-mock/
Use proxyquire and mock promise function
Related
I'm using class-based components in react. I have few components named as follows: Blogs, BlogsClient, BlogCard. When Blogs mounts I make a call to a function inside BlogClient named as getBlogContent to fetch me data using axios.
setBlogs = (blogs) => {
this.setState({ "blogs": blogs });
}
componentDidMount() {
getBlogContent(this.setBlogs);
}
where getBlogContent is:
let getBlogContent = (setBlogs) => {
store.set('loaded', false);
axios.get(ADMIN_URL + '/getAllBlogs')
.then(response => {
store.set('loaded', true);
setBlogs(response.data.Response);
})
.catch(error => {
store.set('loaded', true);
store.set('errorMessage', error);
})
}
I'm able to fetch data and update my state properly. But If there comes any error inside Blogs or BlogCard(which is called inside Blogs) it goes inside the catch of getBlogContent whereas it should be only responsible for catching Axios error. What am I missing here?
Ok, so it's hard to tell without knowing these errors..
But nonetheless, you should avoid setting the component's state outside that component. So, your code'd become:
componentDidMount() {
const blogContent = getBlogContent();
if (blogContent !== 'error'j this.setBlogs(blogContent);
}
let getBlogContent = () => {
store.set('loaded', false);
return axios.get(ADMIN_URL + '/getAllBlogs')
.then(response => {
store.set('loaded', true);
return response.data.Response;
})
.catch(error => {
store.set('loaded', true);
store.set('errorMessage', error);
return 'error';
})
}
i'm new in react and i've got some issues with asynchronous fetch data :
i want to fetch github users
function fetchUser(username) {
return fetch(`https://api.github.com/users/${username}`)
.then(response => response.json())
.then(data => data)
}
export function getUserData(username) {
const object = {
profile: fetchUser(username),
}
console.log(object)
return object
}
and this is my method in my component
componentDidMount() {
getUserData(this.props.playerOne)
}
but this is what i got in my console
{profile: Promise}
i'm sure that i dont understand well this promise so could you help me to have not a Promise in my object but the data i'm fetching ? (if i log data in my fetch i got what i want)
You can make this function async and wait for the promise resolution.
export async function getUserData(username) {
const object = {
profile: await fetchUser(username),
}
console.log(object)
return object
}
then in your componentDidMount
componentDidMount() {
getUserData(this.props.playerOne)
.then((profile) => { this.setState({ profile }) })
}
I am trying to send post request using axios in Reactjs.
I have two component a timer component and App component and in App component i am trying to submit a form and send an axios call when i fetch the time from Timer component and save itinto counter state
I have written a condition if counter is true then update my state and then further send the post request
Working Demo
here is a handle submit code:
const handleSubmit = e => {
console.log("handleSubmit");
e.preventDefault();
if (counter) {
console.log(counter);
const url = `url string`;
setState({
...state,
lastn: {
attestedTime: myDateFunc(),
time: counter
}
});
console.log(state);
axios
.post(url, state)
.then(response => {
console.log(response);
console.log(response.data);
})
.catch(error => {
console.log(error);
});
}
};
The problem is when counter is true its not update the state which causes error while send axios request.
I have consoled each and every thing but still it fails.
It seems there is lot of rendering.
If you are using class components, you can make the reuqest after the state has been set. Something like this:
this.setState({
...state,
lastn: {
attestedTime: myDateFunc(),
time: counter
}
}, () => {
axios
.post(url, state)
.then(response => {
console.log(response);
console.log(response.data);
})
.catch(error => {
console.log(error);
});
});
Since you did set the react-hooks tag, I guess that approach is not what you need. In your case, I suggest saving new state in some temporary variable and than passing that variable to axios. Like this:
const newState = {
...state,
lastn: {
attestedTime: myDateFunc(),
time: counter
}
};
setState(newState);
axios
.post(url, newState)
.then(response => {
console.log(response);
console.log(response.data);
})
.catch(error => {
console.log(error);
});
setState can be executed asynchronously by React, to optimize the rendering process. For cases like this one, it can also take a callback function that is guaranteed to be executed after updating the state.
For example:
this.setState({
name:'value'
},() => {
console.log(this.state.name);
});
in this case console.log will be executed after setting the name variable.
see the docs: https://reactjs.org/docs/react-component.html#setstate
In my Context I have a LocalFunction that returns a promise.
LocalFunction: () => Promise<void>
LocalFunction: () => {
return externalCall.getBooks().then((books) => {
this.setState({ Books: books })
})
}
I can call this function in another component based on the updated Books object in the Context state like:
this.props.LocalFunction().then(() => {
// do something with this.props.Context.Books
})
But I know React updates states in batches. So could I run into a race condition when calling LocalFunction without the Books state being updated with the new books?
I know a way to avoid it is to wrap LocalFunction in a new Promise and resolve it in this.setState({ Books: books }, resolve), but I wanna avoid doing that if possible.
How about to use async/await?
LocalFunction: async (needUpdate = false) => {
const result = await externalCall.getBooks();
if(needUpdate){
this.setState({ Books: result })
}
return result;
}
this.props.LocalFunction().then((res) => {
console.log(res)
// do something with this.props.Context.Books
})
When you need to update state
LocalFunction(true)
How to rewrite the function so that it is updated and loaded every time you change pages. The fact is that the loading function works only on one page, but it does not pass to others, how to change it?
function loadModel(model) {
return function(dispatch) {
dispatch(moveToPending(model))
const resource = require(`../resources/${model}`)
const resourceActions = bindActionCreators(resource.actions, dispatch)
const toaster = new Toaster(dispatch)
return new Promise((resolve, reject) => {
resourceActions[getFunctionName(model)]()
.then(res => {
resolve(model)
dispatch(resolveSubscriptions(model))
})
.catch(err => {
if (debug) console.error(err)
reject({ ...err, model })
dispatch(resolveSubscriptions(model))
toaster.error(`Could not load ${model}!`)
})
})
}
}
Update.
Here's the componentWillMount(), I already have it, what do I need to add to it?
componentWillMount() {
this.props.actions.subscribe(this.subscriptions)
.then(() => {
this.props.actions.fetchRegisters({year: this.state.currentYear, month: defaultMonths()})
.then(() => {
if (!this.props.registers.length) {
this.toaster.warning('There is no data for charts')
}
this.createReportState()
})
})
}
React has some lifecycle methods. You can use componentWillMount or componentDidMount for this purpose. You can pass this function as a prop to other pages and there you can call it in componentWillMount, something like:
componentWillMount() {
this.props.loadModel(//arg);
}
For reference: Component life-cycle methods