Wrapping fetch(), preserve promise-based API for outer function
One of my react component's methods is using an async fetch() internally. After fetching the response from the server, it is being converted to JSON, then I perform a check on that JSON string. Finally, I return the result wrapped in a new promise. Here is the code:
fetchCalendarData(offset, length) {
return fetch(this.props.Uri + '?offset=' + offset + '&length=' + length)
.then(response => response.json())
.then((result) => {
if (result.hasOwnProperty('redirect_to_login') && result.redirect_to_login == true) {
window.location.reload(window.globalAppState.base_url + "/login");
}
return Promise.resolve(result);
})
.catch(() => {
return Promise.reject('FAILURE');
});
}
When I call the method, I do it like this:
this.fetchCalendarData(0, 6).then((fetched_calendar_data) => {
this.calendar_data = fetched_calendar_data;
});
The code works, but I am not familiar with promise based flow at all, and those 3 return statements look a little weird to me. I also read about the promise constructor antipattern but am not sure if that applies here. And, is it necessary to return the result wrapped in a new promise, at all?
javascript react.js promise
asked 2 hours ago
BenniBenni
1061
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One of my react component's methods is using an async fetch() internally. After fetching the response from the server, it is being converted to JSON, then I perform a check on that JSON string. Finally, I return the result wrapped in a new promise. Here is the code:
fetchCalendarData(offset, length) {
return fetch(this.props.Uri + '?offset=' + offset + '&length=' + length)
.then(response => response.json())
.then((result) => {
if (result.hasOwnProperty('redirect_to_login') && result.redirect_to_login == true) {
window.location.reload(window.globalAppState.base_url + "/login");
}
return Promise.resolve(result);
})
.catch(() => {
return Promise.reject('FAILURE');
});
}
When I call the method, I do it like this:
this.fetchCalendarData(0, 6).then((fetched_calendar_data) => {
this.calendar_data = fetched_calendar_data;
});
The code works, but I am not familiar with promise based flow at all, and those 3 return statements look a little weird to me. I also read about the promise constructor antipattern but am not sure if that applies here. And, is it necessary to return the result wrapped in a new promise, at all?
javascript react.js promise
asked 2 hours ago
BenniBenni
1061
New contributor
Benni is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
add a comment |
One of my react component's methods is using an async fetch() internally. After fetching the response from the server, it is being converted to JSON, then I perform a check on that JSON string. Finally, I return the result wrapped in a new promise. Here is the code:
fetchCalendarData(offset, length) {
return fetch(this.props.Uri + '?offset=' + offset + '&length=' + length)
.then(response => response.json())
.then((result) => {
if (result.hasOwnProperty('redirect_to_login') && result.redirect_to_login == true) {
window.location.reload(window.globalAppState.base_url + "/login");
}
return Promise.resolve(result);
})
.catch(() => {
return Promise.reject('FAILURE');
});
}
When I call the method, I do it like this:
this.fetchCalendarData(0, 6).then((fetched_calendar_data) => {
this.calendar_data = fetched_calendar_data;
});
The code works, but I am not familiar with promise based flow at all, and those 3 return statements look a little weird to me. I also read about the promise constructor antipattern but am not sure if that applies here. And, is it necessary to return the result wrapped in a new promise, at all?
javascript react.js promise
asked 2 hours ago
BenniBenni
1061
New contributor
Benni is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
One of my react component's methods is using an async fetch() internally. After fetching the response from the server, it is being converted to JSON, then I perform a check on that JSON string. Finally, I return the result wrapped in a new promise. Here is the code:
fetchCalendarData(offset, length) {
return fetch(this.props.Uri + '?offset=' + offset + '&length=' + length)
.then(response => response.json())
.then((result) => {
if (result.hasOwnProperty('redirect_to_login') && result.redirect_to_login == true) {
window.location.reload(window.globalAppState.base_url + "/login");
}
return Promise.resolve(result);
})
.catch(() => {
return Promise.reject('FAILURE');
});
}
When I call the method, I do it like this:
this.fetchCalendarData(0, 6).then((fetched_calendar_data) => {
this.calendar_data = fetched_calendar_data;
});
The code works, but I am not familiar with promise based flow at all, and those 3 return statements look a little weird to me. I also read about the promise constructor antipattern but am not sure if that applies here. And, is it necessary to return the result wrapped in a new promise, at all?
javascript react.js promise
javascript react.js promise
asked 2 hours ago
BenniBenni
1061
New contributor
Benni is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
asked 2 hours ago
BenniBenni
1061
New contributor
Benni is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
asked 2 hours ago
BenniBenni
1061
New contributor
Benni is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
asked 2 hours ago
BenniBenni
1061
asked 2 hours ago
BenniBenni
1061
1061
New contributor
Benni is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
New contributor
Benni is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
Benni is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
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