ekyc

Electronic KYC process with uploading ID document using OAuth 2.1 (experimental)
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limiter.ts (1015B)

      1 import { Ephemeral } from "#core/domain/ephemeral.ts";
      2 import { DomainError } from "#core/domain/error.ts";
      3 
      4 export class ExceedingLimit extends DomainError {
      5   constructor(readonly delay: number) {
      6     super(`Exceeding limit`);
      7   }
      8 }
      9 
     10 export class Limiter {
     11   private _counter: Ephemeral<number>;
     12 
     13   constructor(
     14     readonly limit: number,
     15     readonly ttl: number,
     16     count: number = 0,
     17     expire: number = 0,
     18   ) {
     19     this._counter = new Ephemeral(count, expire);
     20   }
     21 
     22   get count(): number {
     23     return this._counter.orElse(0);
     24   }
     25 
     26   get expire(): number {
     27     return this._counter.expire;
     28   }
     29 
     30   get delay() {
     31     if (this.remaining > 0) return 0;
     32     return this._counter.ttl;
     33   }
     34 
     35   get remaining(): number {
     36     return Math.max(this.limit - this.count, 0);
     37   }
     38 
     39   increment(): void {
     40     if (this.remaining === 0) {
     41       throw new ExceedingLimit(this.delay);
     42     }
     43     const ttl = this._counter.ttl;
     44     this._counter = Ephemeral.of(
     45       this.count + 1,
     46       ttl > 0 ? ttl : this.ttl,
     47     );
     48   }
     49 }