feat: Add Momentum to Accelerator Oscillator (#290)

src/AC/AC.test.ts

@@ -258,6 +258,7 @@ describe('AC', () => {
       // https://github.com/jesse-ai/jesse/blob/53297462d48ebf43f9df46ab5005076d25073e5e/tests/test_indicators.py#L14
       expect(ac.isStable).toBeTrue();
       expect(ac.getResult().toFixed(2)).toBe('-21.97');
+      expect(ac.momentum.getResult().toFixed(2)).toBe('-9.22');
     });
 
     it('throws an error when there is not enough input data', () => {

src/AC/AC.ts

@@ -3,6 +3,7 @@ import Big, {BigSource} from 'big.js';
 import {NotEnoughDataError} from '../error';
 import {AO} from '../AO/AO';
 import {SMA} from '../SMA/SMA';
+import {MOM} from '../MOM/MOM';
 
 /**
  * The Accelerator Oscillator (AC) is an indicator used to detect when a momentum changes. It has been developed by
@@ -12,13 +13,15 @@ import {SMA} from '../SMA/SMA';
  * change of momentum.
  */
 export class AC implements SimpleIndicator {
+  public readonly momentum: MOM;
   private readonly ao: AO;
   private result: Big | undefined;
   private readonly signalSMA: SMA;
 
   constructor(public readonly shortAO: number, public readonly longAO: number, public readonly signalInterval: number) {
     this.ao = new AO(shortAO, longAO);
     this.signalSMA = new SMA(signalInterval);
+    this.momentum = new MOM(1);
   }
 
   get isStable(): boolean {
@@ -40,6 +43,7 @@ export class AC implements SimpleIndicator {
       this.signalSMA.update(ao);
       if (this.signalSMA.isStable) {
         this.result = ao.sub(this.signalSMA.getResult());
+        this.momentum.update(this.result);
       }
     }
   }