ajel-go/ajel-strict-error-instanceof
This rule enforces narrowing the error type with
instanceof.
Summary
The ajel-strict-error-instanceof rule ensures that when calling ajel, the error variable is properly narrowed using the instanceof operator. This helps developers perform more specific error handling and enhances the type safety of the code.
Rule Details
This rule checks for variable declarations associated with an ajel call and ensures that the error variable is subsequently narrowed using the instanceof operator in a BinaryExpression.
Why is this Rule Useful?
Properly narrowing the error type with instanceof promotes more precise error handling.
Options
ajelAlias(default: 'ajel'): Specify the alias for the ajel method. This allows you to customize the method name if it differs from the default 'ajel'.sjelAlias(default: 'sjel'): Specify the alias for the sjel method. This allows you to customize the method name if it differs from the default 'sjel'.
Implementation
Examples
// ajel
// Bad: Error variable not narrowed with instanceof
const [data, err] = await ajel(Promise.resolve(1));
// Missing instanceof check for specific error type
if (err) {
console.error(err);
}
// Good: Error variable narrowed with instanceof
const [data, err] = await ajel(Promise.resolve(1));
// Handle specific error type
if (err instanceof SpecificError) {
console.error(err.message);
}
// -----
// sjel
// Bad: Error variable not narrowed with instanceof
const [data, err] = sjel(() => 1)();
// Missing instanceof check for specific error type
if (err) {
console.error(err);
}
// Good: Error variable narrowed with instanceof
const [data, err] = sjel(() => 1)();
// Handle specific error type
if (err instanceof SpecificError) {
console.error(err.message);
}