TypeScript Class Decorator Passing arguments to a class decorator
Example
We can wrap a class decorator with another function to allow customization:
function addMetadata(metadata: any) {
return function log(target: any) {
// Add metadata
target.__customMetadata = metadata;
// Return target
return target;
}
}
The addMetadata takes some arguments used as configuration and then returns an unnamed function which is the actual decorator. In the decorator we can access the arguments because there is a closure in place.
We can then invoke the decorator passing some configuration values:
@addMetadata({ guid: "417c6ec7-ec05-4954-a3c6-73a0d7f9f5bf" })
class Person {
private _name: string;
public constructor(name: string) {
this._name = name;
}
public greet() {
return this._name;
}
}
We can use the following function to access the generated metadata:
function getMetadataFromClass(target: any) {
return target.__customMetadata;
}
console.log(getMetadataFromInstance(Person));
If everything went right the console should display:
{ guid: "417c6ec7-ec05-4954-a3c6-73a0d7f9f5bf" }
