@magna_shogun/catch-decorator
v1.0.1
Published
Handle exceptions by just annotating a method or class with a decorator. Based on enkot/catch-decorator.
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Catch Decorator
ECMAScript/TypeScript Catch decorator for classes and functions. Based on @enkot/catch-decorator.
Install
npm install @magna_shogun/catch-decorator
yarn add @magna_shogun/catch-decorator
Usage
catch-decorator
works with any ECMAScript/TypeScript class. If you use Babel, babel-plugin-transform-decorators-legacy is needed. If you use TypeScript, enable--experimentalDecorators
flag.
Catch
Decorate a function to catch the specific type of error.
class Messenger {
@Catch(ReferenceError, (err, ctx) => {...})
getMessages() {
throw new ReferenceError('ReferenceError here!');
...
}
}
You can stack decorators to catch and handle different types of error.
class Messenger {
@Catch(TypeError, (err, ctx) => {...})
@Catch(ReferenceError, (err, ctx) => {...})
getMessages() {
if (conditionA) {
throw new ReferenceError('ReferenceError here!');
...
}
if (conditionB) {
throw new TypeError('TypeError here!');
...
}
}
}
It also works for async
functions.
class Messenger {
@Catch(ServerError, (err, ctx) => {...})
async getMessages() {
return fetch(myRequest).then(response => { // can throw ServerError
...
});
}
}
CatchAll
You can catch any type of errors using the CatchAll
decorator.
class Messenger {
@CatchAll((err, ctx) => {...})
getMessages() {
// Both ReferenceError and TypeError will be catched
if (conditionA) {
throw new ReferenceError('ReferenceError here!');
...
}
if (conditionB) {
throw new TypeError('TypeError here!');
...
}
}
}
Class Decoration
If you want to apply the same decorator to all the functions of a class (excluding its constructor), you can add the decorator to the class.
class Messenger {
@Catch(ReferenceError, (err, ctx) => {...})
getMessages() {
throw new ReferenceError('ReferenceError here!');
...
}
@Catch(ReferenceError, (err, ctx) => {...})
getPosts() {
throw new ReferenceError('ReferenceError here!');
...
}
}
This can be re-written as follows.
@Catch(ReferenceError, (err, ctx) => {...})
class Messenger {
getMessages() {
throw new ReferenceError('ReferenceError here!');
...
}
getPosts() {
throw new ReferenceError('ReferenceError here!');
...
}
}
HandlerFunction
The callback for the Catch
and CatchAll
decorators is of type HandlerFunction
.
type HandlerFunction = (error: Error, ctx: any) => void;
error
is the caught error or exception.ctx
is the context (this
) of the function were the error was thrown.
License
MIT