I am creating my own Typescript decorators for validation, but they are not working together, only the first decorator is activated, the second is ignored. The property errors should have a value, because the length passed is less than 3 characters, but is returning undefined.

function IsMoreThan(length: number) {
  return (target: any, propertyKey: string) => {
    let val = target[propertyKey];

    const getter = () => val;
    const setter = (value: string) => {
      if (value.length <= length) {
        Object.defineProperty(target, 'errors', {
          value: `${propertyKey} must be more than ${length} characters`,
          configurable: true,
        });
      } else {
        val = value;
      }
    };

    Object.defineProperty(target, propertyKey, {
      get: getter,
      set: setter,
      configurable: true,
    });
  };
}

function IsString() {
  return (target: any, propertyKey: string) => {
    let val = target[propertyKey];

    const getter = () => val;
    const setter = (value: string) => {
      const varType = typeof value;
      if (varType !== 'string') {
        Object.defineProperty(target, 'errors', {
          value: `${propertyKey} must be a string, received ${varType}`,
          configurable: true,
        });
      } else {
        val = value;
      }
    };

    Object.defineProperty(target, propertyKey, {
      get: getter,
      set: setter,
      configurable: true,
    });
  };
}

class CreateUserSerializer {
  @IsString()
  @IsMoreThan(3)
  public username: string;

  constructor(username: string) {
    this.username = username;
  }
}

const user = new CreateUserSerializer('aa');
console.log(user.errors);

Here is a playground with the code for easier testing: TS Playground