typescript
1class ValidationChain {
2  private handlers: AddressHandler[] = [];
3
4  add(handler: AddressHandler): this {
5    this.handlers.push(handler);
6    return this;
7  }
8
9  build(): AddressHandler {
10    for (let i = 0; i < this.handlers.length - 1; i++) {
11      this.handlers[i].setNext(this.handlers[i + 1]);
12    }
13    return this.handlers[0];
14  }
15}
16
17// Usage
18const chain = new ValidationChain()
19  .add(new FormatValidator())
20  .add(new PostalCodeValidator())
21  .add(new GeocodingValidator())
22  .build();