New: trim extra zeroes in prices

src/prices/Price.js

@@ -6,6 +6,25 @@ export default class Price {
     }
 
     get prettyPrice() {
-        return this.price.toFixed(this.precision).toString(); // TODO: drop trailing spaces
+        const str = this.price.toFixed(this.precision).toString();
+
+        if (!str.includes('.')) return str;
+
+        let trimFrom = str.length;
+
+        for (const char of [ ...str ].reverse()) {
+            if (char === '0') {
+                trimFrom--; continue;
+            }
+
+            if (char === '.') {
+                trimFrom--; break;
+            }
+
+            break;
+        }
+
+
+        return  str.slice(0, trimFrom);
     }
 }

tests/unit/getPrice.test.js → tests/unit/exchangeGetPrice.test.js

@@ -5,7 +5,7 @@ import Binance from '../../src/exchanges/Binance';
 const exchange = new Binance();
 const factory = new Test();
 
-suite('unit: getPrice [binance]');
+suite('unit: exchange.getPrice [binance]');
 
 before(async function () {
     factory.mockAPI();

tests/unit/pricePrettyPrice.test.js

@@ -0,0 +1,23 @@
+import { assert } from 'chai';
+import '../Test';
+import Price from '../../src/prices/Price';
+
+
+suite('unit: price.prettyPrice');
+
+test('leave good prices as is', async function () {
+    assert.equal((new Price(12.123_456_78)).prettyPrice, '12.12345678');
+});
+
+test('round over precision', async function () {
+    assert.equal((new Price(12.123_456_781)).prettyPrice, '12.12345678');
+    assert.equal((new Price(12.123_456_786)).prettyPrice, '12.12345679');
+});
+
+test('trim extra zeroes', async function () {
+    assert.equal((new Price(12.123)).prettyPrice, '12.123');
+    assert.equal((new Price(100)).prettyPrice, '100');
+    assert.equal((new Price(12)).prettyPrice, '12');
+    assert.equal((new Price(1.000_000_000_000_000_001)).prettyPrice, '1');
+    assert.equal((new Price(0.000_000_000_000_000_01)).prettyPrice, '0');
+});