Typescript Decorator Validate

1// decorators/validate.ts
2export function Validate(params: Array<any>): any {
3  return (target: Object, propertyKey: string): TypedPropertyDescriptor<any> => {
4    const descriptor = Object.getOwnPropertyDescriptor(target, propertyKey);
5    const originalMethod = descriptor.value;
6
7    descriptor.value = function () {
8      const errors: Array<any> = [];
9      const body = arguments[0];
10
11      params.forEach((currentParam: any) => {
12        switch (currentParam.validate) {
13          case 'email':
14            const check = new RegExp('\\b[\\w\\.-]+@[\\w\\.-]+\\.\\w{2,4}\\b', 'gi');
15            if (!check.test(body[currentParam.param])) {
16              errors.push(currentParam);
17            }
18          break;
19          case 'required':
20          default:
21            if (!body[currentParam.param]) {
22              errors.push(currentParam);
23            }
24          break;
25        }
26      });
27
28      if (errors.length) {
29        return Promise.reject(errors);
30      } else {
31        return originalMethod.apply(this, arguments);
32      }
33    };
34
35    return descriptor;
36  };
37}
38
39
40// Usage
41import { Validate } from '../decorators/Validate';
42
43@Post()
44@Validate([
45  {
46    param: 'bannerSetId',
47    validate: 'required'
48  }
49])