mirror of
https://git.proxmox.com/git/pve-eslint
synced 2025-10-04 14:38:51 +00:00
eb39fafa4f
includes a (minimal) working wrapper Signed-off-by: Dominik Csapak <d.csapak@proxmox.com>
80 lines
2.7 KiB
Markdown
80 lines
2.7 KiB
Markdown
# require using Error objects as Promise rejection reasons (prefer-promise-reject-errors)
|
|
|
|
It is considered good practice to only pass instances of the built-in `Error` object to the `reject()` function for user-defined errors in Promises. `Error` objects automatically store a stack trace, which can be used to debug an error by determining where it came from. If a Promise is rejected with a non-`Error` value, it can be difficult to determine where the rejection occurred.
|
|
|
|
|
|
## Rule Details
|
|
|
|
This rule aims to ensure that Promises are only rejected with `Error` objects.
|
|
|
|
## Options
|
|
|
|
This rule takes one optional object argument:
|
|
|
|
* `allowEmptyReject: true` (`false` by default) allows calls to `Promise.reject()` with no arguments.
|
|
|
|
Examples of **incorrect** code for this rule:
|
|
|
|
```js
|
|
/*eslint prefer-promise-reject-errors: "error"*/
|
|
|
|
Promise.reject("something bad happened");
|
|
|
|
Promise.reject(5);
|
|
|
|
Promise.reject();
|
|
|
|
new Promise(function(resolve, reject) {
|
|
reject("something bad happened");
|
|
});
|
|
|
|
new Promise(function(resolve, reject) {
|
|
reject();
|
|
});
|
|
|
|
```
|
|
|
|
Examples of **correct** code for this rule:
|
|
|
|
```js
|
|
/*eslint prefer-promise-reject-errors: "error"*/
|
|
|
|
Promise.reject(new Error("something bad happened"));
|
|
|
|
Promise.reject(new TypeError("something bad happened"));
|
|
|
|
new Promise(function(resolve, reject) {
|
|
reject(new Error("something bad happened"));
|
|
});
|
|
|
|
var foo = getUnknownValue();
|
|
Promise.reject(foo);
|
|
```
|
|
|
|
Examples of **correct** code for this rule with the `allowEmptyReject: true` option:
|
|
|
|
```js
|
|
/*eslint prefer-promise-reject-errors: ["error", {"allowEmptyReject": true}]*/
|
|
|
|
Promise.reject();
|
|
|
|
new Promise(function(resolve, reject) {
|
|
reject();
|
|
});
|
|
```
|
|
|
|
## Known Limitations
|
|
|
|
Due to the limits of static analysis, this rule cannot guarantee that you will only reject Promises with `Error` objects. While the rule will report cases where it can guarantee that the rejection reason is clearly not an `Error`, it will not report cases where there is uncertainty about whether a given reason is an `Error`. For more information on this caveat, see the [similar limitations](no-throw-literal.md#known-limitations) in the `no-throw-literal` rule.
|
|
|
|
To avoid conflicts between rules, this rule does not report non-error values used in `throw` statements in async functions, even though these lead to Promise rejections. To lint for these cases, use the [`no-throw-literal`](https://eslint.org/docs/rules/no-throw-literal) rule.
|
|
|
|
## When Not To Use It
|
|
|
|
If you're using custom non-error values as Promise rejection reasons, you can turn off this rule.
|
|
|
|
## Further Reading
|
|
|
|
* [`no-throw-literal`](https://eslint.org/docs/rules/no-throw-literal)
|
|
* [Warning: a promise was rejected with a non-error](http://bluebirdjs.com/docs/warning-explanations.html#warning-a-promise-was-rejected-with-a-non-error)
|