feat(MA,SMA,TR): Expose "replace" function

README.md

@@ -86,7 +86,7 @@ sma.updates([20, 40, 80]);
 sma.update('10');
 
 // You can replace a previous value (useful for live charts):
-sma.update('40', true);
+sma.replace('40');
 
 // You can add arbitrary-precision decimals:
 sma.update(new Big(30));

src/Indicator.ts

@@ -60,7 +60,11 @@ export abstract class BigIndicatorSeries<Input = BigSource> implements Indicator
     return (this.result = value);
   }
 
-  abstract update(input: Input): void | Big;
+  abstract update(input: Input, replace?: boolean): void | Big;
+
+  replace(input: Input) {
+    return this.update(input, true);
+  }
 }
 
 export abstract class NumberIndicatorSeries<Input = number> implements IndicatorSeries<number, Input> {
@@ -104,5 +108,9 @@ export abstract class NumberIndicatorSeries<Input = number> implements Indicator
     return (this.result = value);
   }
 
-  abstract update(input: Input): void | number;
+  abstract update(input: Input, replace?: boolean): void | number;
+
+  replace(input: Input) {
+    return this.update(input, true);
+  }
 }

src/MA/MovingAverage.ts

@@ -20,6 +20,10 @@ export abstract class MovingAverage extends BigIndicatorSeries {
   }
 
   abstract update(price: BigSource, replace?: boolean): Big | void;
+
+  replace(price: BigSource) {
+    return this.update(price, true);
+  }
 }
 
 export abstract class FasterMovingAverage extends NumberIndicatorSeries {
@@ -33,4 +37,8 @@ export abstract class FasterMovingAverage extends NumberIndicatorSeries {
   }
 
   abstract update(price: number, replace?: boolean): number | void;
+
+  replace(price: number) {
+    return this.update(price, true);
+  }
 }

src/SMA/SMA.test.ts

@@ -20,7 +20,7 @@ describe('SMA', () => {
   });
 
   describe('update', () => {
-    it('can replace recently added values', () => {
+    it('replaces recently added values', () => {
       const interval = 3;
 
       const sma = new SMA(interval);
@@ -32,17 +32,26 @@ describe('SMA', () => {
       sma.update(30);
       fasterSMA.update(30);
 
+      // Add the last candle
       sma.update(40);
       fasterSMA.update(40);
 
       expect(sma.getResult().toFixed()).toBe('30');
       expect(fasterSMA.getResult().toFixed()).toBe('30');
 
-      sma.update(10, true);
-      fasterSMA.update(10, true);
+      // Replace the last candle with some other candle
+      sma.replace(10);
+      fasterSMA.replace(10);
 
       expect(sma.getResult().toFixed()).toBe('20');
       expect(fasterSMA.getResult().toFixed()).toBe('20');
+
+      // Replace other candle again with the last candle
+      sma.replace(40);
+      fasterSMA.replace(40);
+
+      expect(sma.getResult().toFixed()).toBe('30');
+      expect(fasterSMA.getResult().toFixed()).toBe('30');
     });
   });
 

src/TR/TR.test.ts

@@ -19,7 +19,7 @@ describe('TR', () => {
     {close: 86.89, high: 86.98, low: 85.76},
     {close: 87.77, high: 88.0, low: 87.17},
     {close: 87.29, high: 87.87, low: 87.01},
-  ];
+  ] as const;
   const expectations = [
     '0.86',
     '1.25',
@@ -36,7 +36,7 @@ describe('TR', () => {
     '1.22',
     '1.11',
     '0.86',
-  ];
+  ] as const;
 
   describe('getResult', () => {
     it('calculates the True Range (TR)', () => {
@@ -89,17 +89,17 @@ describe('TR', () => {
       expect(tr.getResult().toFixed(2)).toBe(expected);
       expect(fasterTR.getResult().toFixed(2)).toBe(expected);
 
-      // Replace the last candle with some other candle.
-      tr.update(otherCandle, true);
-      fasterTR.update(otherCandle, true);
+      // Replace the last candle with some other candle
+      tr.replace(otherCandle);
+      fasterTR.replace(otherCandle);
 
       expect(tr.getResult().toFixed(2)).not.toBe(expected);
       expect(fasterTR.getResult().toFixed(2)).not.toBe(expected);
 
-      // Replace other candle again with the last candle.
+      // Replace other candle again with the last candle
       if (lastCandle) {
-        tr.update(lastCandle, true);
-        fasterTR.update(lastCandle, true);
+        tr.replace(lastCandle);
+        fasterTR.replace(lastCandle);
       }
 
       expect(tr.getResult().toFixed(2)).toBe(expected);