diff --git a/src/AC/AC.ts b/src/AC/AC.ts
index 80a7afb55..c564efb0d 100644
--- a/src/AC/AC.ts
+++ b/src/AC/AC.ts
@@ -24,11 +24,11 @@ export class AC extends SimpleIndicator {
     this.momentum = new MOM(1);
   }
 
-  get isStable(): boolean {
+  override get isStable(): boolean {
     return this.result !== undefined;
   }
 
-  getResult(): Big {
+  override getResult(): Big {
     if (!this.result) {
       throw new NotEnoughDataError();
     }
@@ -36,7 +36,7 @@ export class AC extends SimpleIndicator {
     return this.result;
   }
 
-  update(low: BigSource, high: BigSource): void | Big {
+  override update(low: BigSource, high: BigSource): void | Big {
     const ao = this.ao.update(low, high);
     if (ao) {
       this.signal.update(ao);
diff --git a/src/AO/AO.ts b/src/AO/AO.ts
index 472212f41..d9b28ea1a 100644
--- a/src/AO/AO.ts
+++ b/src/AO/AO.ts
@@ -17,11 +17,11 @@ export class AO extends SimpleIndicator {
     this.long = new SMA(longInterval);
   }
 
-  get isStable(): boolean {
+  override get isStable(): boolean {
     return this.result !== undefined;
   }
 
-  getResult(): Big {
+  override getResult(): Big {
     if (!this.result) {
       throw new NotEnoughDataError();
     }
@@ -29,7 +29,7 @@ export class AO extends SimpleIndicator {
     return this.result;
   }
 
-  update(low: BigSource, high: BigSource): void | Big {
+  override update(low: BigSource, high: BigSource): void | Big {
     const candleSum = new Big(low).add(high);
     const medianPrice = candleSum.div(2);
 
diff --git a/src/ATR/ATR.ts b/src/ATR/ATR.ts
index e37c5b822..fe5f3bf6b 100644
--- a/src/ATR/ATR.ts
+++ b/src/ATR/ATR.ts
@@ -21,11 +21,11 @@ export class ATR extends SimpleIndicator {
     this.smma = new SMMA(interval);
   }
 
-  get isStable(): boolean {
+  override get isStable(): boolean {
     return this.candles.length > this.interval;
   }
 
-  update(candle: ATRCandle): void {
+  override update(candle: ATRCandle): void {
     this.candles.push(candle);
 
     if (!this.prevCandle) {
@@ -49,7 +49,7 @@ export class ATR extends SimpleIndicator {
     this.prevCandle = candle;
   }
 
-  getResult(): Big {
+  override getResult(): Big {
     if (!this.result) {
       throw new NotEnoughDataError();
     }
diff --git a/src/CG/CG.ts b/src/CG/CG.ts
index f086e67b3..c3f3899ca 100644
--- a/src/CG/CG.ts
+++ b/src/CG/CG.ts
@@ -18,7 +18,7 @@ export class CG extends SimpleIndicator {
 
   public readonly prices: Big[] = [];
 
-  get isStable(): boolean {
+  override get isStable(): boolean {
     return this.prices.length >= this.interval && this.signal.isStable;
   }
 
@@ -27,7 +27,7 @@ export class CG extends SimpleIndicator {
     this.signal = new SMA(signalInterval);
   }
 
-  update(price: BigSource): void {
+  override update(price: BigSource): void {
     this.prices.push(new Big(price));
 
     if (this.prices.length > this.interval) {
@@ -50,7 +50,7 @@ export class CG extends SimpleIndicator {
     this.setResult(cg);
   }
 
-  getResult(): Big {
+  override getResult(): Big {
     if (!this.isStable || !this.result) {
       throw new NotEnoughDataError();
     }
diff --git a/src/DEMA/DEMA.ts b/src/DEMA/DEMA.ts
index 8f3df6795..fdeb32cde 100644
--- a/src/DEMA/DEMA.ts
+++ b/src/DEMA/DEMA.ts
@@ -12,13 +12,13 @@ export class DEMA extends SimpleIndicator {
     this.outer = new EMA(interval);
   }
 
-  update(price: BigSource): void {
+  override update(price: BigSource): void {
     this.inner.update(price);
     this.outer.update(this.inner.getResult());
     this.setResult(this.inner.getResult().times(2).sub(this.outer.getResult()));
   }
 
-  get isStable(): boolean {
+  override get isStable(): boolean {
     try {
       this.inner.getResult();
       this.outer.getResult();
@@ -28,7 +28,7 @@ export class DEMA extends SimpleIndicator {
     }
   }
 
-  getResult(): Big {
+  override getResult(): Big {
     if (!this.result) {
       throw new NotEnoughDataError();
     }
diff --git a/src/EMA/EMA.test.ts b/src/EMA/EMA.test.ts
index 23a21842c..6fde7aa73 100644
--- a/src/EMA/EMA.test.ts
+++ b/src/EMA/EMA.test.ts
@@ -17,7 +17,7 @@ describe('EMA', () => {
         ema.update(new Big(price));
         const actual = ema.getResult();
         const expected = new Big(ema10results[index]);
-        expect(actual!.toPrecision(12)).toEqual(expected.toPrecision(12));
+        expect(actual.toPrecision(12)).toEqual(expected.toPrecision(12));
       });
 
       expect(ema.lowest!.toFixed(2)).toBe('38.20');
@@ -45,7 +45,7 @@ describe('EMA', () => {
         ema.update(new Big(price));
         const actual = ema.getResult();
         const expected = new Big(ema26results[index]);
-        expect(actual!.toPrecision(12)).toEqual(expected.toPrecision(12));
+        expect(actual.toPrecision(12)).toEqual(expected.toPrecision(12));
       });
 
       expect(ema.lowest!.toFixed(2)).toBe('48.29');
diff --git a/src/EMA/EMA.ts b/src/EMA/EMA.ts
index 619ac8ecb..273447389 100644
--- a/src/EMA/EMA.ts
+++ b/src/EMA/EMA.ts
@@ -2,7 +2,7 @@ import Big, {BigSource} from 'big.js';
 import {MovingAverage} from '../MA/MovingAverage';
 
 export class EMA extends MovingAverage {
-  update(_price: BigSource): void {
+  override update(_price: BigSource): void {
     const price = new Big(_price);
 
     // If it's the first update there is no previous result and a default has to be set.
diff --git a/src/MA/MovingAverage.ts b/src/MA/MovingAverage.ts
index 728381475..d5ee73b06 100644
--- a/src/MA/MovingAverage.ts
+++ b/src/MA/MovingAverage.ts
@@ -7,11 +7,11 @@ export abstract class MovingAverage extends SimpleIndicator {
     super();
   }
 
-  get isStable(): boolean {
+  override get isStable(): boolean {
     return !!this.result;
   }
 
-  getResult(): Big {
+  override getResult(): Big {
     if (!this.result) {
       throw new NotEnoughDataError();
     }
diff --git a/src/MOM/MOM.ts b/src/MOM/MOM.ts
index 40d34379e..816299e22 100644
--- a/src/MOM/MOM.ts
+++ b/src/MOM/MOM.ts
@@ -16,18 +16,18 @@ export class MOM extends SimpleIndicator {
     this.history = getFixedArray<BigSource>(this.historyLength);
   }
 
-  update(value: BigSource): void {
+  override update(value: BigSource): void {
     this.history.push(value);
     if (this.history.length === this.historyLength) {
       this.setResult(new Big(value).minus(this.history[0]));
     }
   }
 
-  get isStable(): boolean {
+  override get isStable(): boolean {
     return this.result !== undefined;
   }
 
-  getResult(): Big {
+  override getResult(): Big {
     if (!this.result) {
       throw new NotEnoughDataError();
     }
diff --git a/src/ROC/ROC.ts b/src/ROC/ROC.ts
index 0b8661478..f9056ed30 100644
--- a/src/ROC/ROC.ts
+++ b/src/ROC/ROC.ts
@@ -10,11 +10,11 @@ export class ROC extends SimpleIndicator {
     this.interval = interval;
   }
 
-  get isStable(): boolean {
+  override get isStable(): boolean {
     return this.result !== undefined;
   }
 
-  update(_price: BigSource): void {
+  override update(_price: BigSource): void {
     const price = new Big(_price);
 
     this.priceHistory.push(price);
@@ -35,7 +35,7 @@ export class ROC extends SimpleIndicator {
     this.setResult(price.sub(comparePrice).div(comparePrice));
   }
 
-  getResult(): Big {
+  override getResult(): Big {
     if (!this.result) {
       throw new NotEnoughDataError();
     }
diff --git a/src/RSI/RSI.ts b/src/RSI/RSI.ts
index f01168443..b750afa93 100644
--- a/src/RSI/RSI.ts
+++ b/src/RSI/RSI.ts
@@ -14,7 +14,7 @@ export class RSI extends SimpleIndicator {
     this.avgLoss = new Indicator(this.interval);
   }
 
-  update(price: BigSource): void {
+  override update(price: BigSource): void {
     const currentClose = new Big(price);
     this.prices.push(currentClose);
 
@@ -52,14 +52,14 @@ export class RSI extends SimpleIndicator {
     }
   }
 
-  getResult(): Big {
+  override getResult(): Big {
     if (!this.isStable) {
       throw new NotEnoughDataError();
     }
     return this.result!;
   }
 
-  get isStable(): boolean {
+  override get isStable(): boolean {
     if (this.result) {
       return this.result.gt(0);
     }
diff --git a/src/SMA/SMA.ts b/src/SMA/SMA.ts
index 4cd1f9258..14ac99101 100644
--- a/src/SMA/SMA.ts
+++ b/src/SMA/SMA.ts
@@ -4,7 +4,7 @@ import {MovingAverage} from '../MA/MovingAverage';
 export class SMA extends MovingAverage {
   public readonly prices: Big[] = [];
 
-  update(price: BigSource): void {
+  override update(price: BigSource): void {
     this.prices.push(new Big(price));
 
     if (this.prices.length > this.interval) {
diff --git a/src/SMMA/SMMA.ts b/src/SMMA/SMMA.ts
index e48e212ae..db7958153 100644
--- a/src/SMMA/SMMA.ts
+++ b/src/SMMA/SMMA.ts
@@ -11,7 +11,7 @@ class SMMA extends MovingAverage {
     this.sma = new SMA(interval);
   }
 
-  update(price: BigSource): void {
+  override update(price: BigSource): void {
     this.prices.push(new Big(price));
 
     if (this.prices.length < this.interval) {
@@ -33,7 +33,7 @@ class SMMA extends MovingAverage {
     }
   }
 
-  getResult(): Big {
+  override getResult(): Big {
     return this.result || new Big(0);
   }
 }