Add decorators.ts

This commit is contained in:
Zakary Timson 2023-08-03 00:32:32 +00:00
parent 590b862263
commit de23450fb5

54
decorators.ts Normal file
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// Class decorator
function seal(constructor: Function) {
Object.seal(constructor);
Object.seal(constructor.prototype);
}
// Method decorator
function setTimeout(ms = 0) { // Notice the wrapper function to get arguments, this can be done to any decorator function
return function(target: any, propertyKey: string, descriptor: PropertyDescriptor) {
const originalMethod = descriptor.value;
descriptor.value = function () {
setTimeout(() => originalMethod.apply(this, arguments), ms);
};
return descriptor;
}
}
// Accessor/Property decorator
function log(target: any, key: string) {
let value = target[key];
Object.defineProperty(target, key, {
get: () => {
console.log(`Get => ${key}`);
return value;
},
set: (newValue) => {
console.log(`Set: ${key} => ${e}`);
value = newValue;
},
enumerable: true,
configurable: true
});
}
// Example
@seal
class Person {
@log firstName: string;
@log lastName: string;
@log
get name() { return `${this.firstName} ${this.lastName}`};
constructor(firstName: string, lastName: string) {
this.firstName = firstName;
this.lastName = lastName;
}
@timeout(1000)
whoami() {
return this.name;
}
}