feat: add decimalTrailingZeroesToExponent function

coingecko · Dec 11, 2023 · f53df3f · f53df3f
1 parent cfa851e
commit f53df3f
Showing 1 changed file with 28 additions and 8 deletions.
diff --git a/src/index.js b/src/index.js
@@ -72,8 +72,22 @@ export function isCrypto(isoCode) {
   return isBTCETH(isoCode) || supportedCurrencySymbols[isoCode] == null;
 }
 
+// Function to transform decimal trailing zeroes to exponent
+function decimalTrailingZeroesToExponent(formattedCurrency, maximumTrailingDecimalZeroes) {
+  const decimalTrailingZeroesPattern = new RegExp(`\\.(0{${maximumTrailingDecimalZeroes + 1},})(?=[1-9]?)`);
+
+  return formattedCurrency.replace(
+      decimalTrailingZeroesPattern,
+      (match, decimalTrailingZeroes) => `.0<sub title=${formattedCurrency}>${decimalTrailingZeroes.length}</sub>`,
+  )
+}
+
 // Function to transform the output from Intl.NumberFormat#format
-function formatCurrencyOverride(formattedCurrency, locale = "en") {
+function formatCurrencyOverride(formattedCurrency, locale = "en", maximumTrailingDecimalZeroes) {
+  if (typeof maximumTrailingDecimalZeroes !== "undefined") {
+    formattedCurrency = decimalTrailingZeroesToExponent(formattedCurrency, maximumTrailingDecimalZeroes)
+  }
+
   // If currency code remains in front
   const currencyCodeFrontMatch = formattedCurrency.match(/^[A-Z]{3}\s?/);
   if (currencyCodeFrontMatch != null) {
@@ -277,6 +291,7 @@ export function formatCurrency(
   abbreviated = false,
 ) {
   isoCode = isoCode.toUpperCase();
+  let maximumTrailingDecimalZeroes = undefined;
 
   if (currentISOCode !== isoCode || currentLocale != locale) {
     currentISOCode = isoCode;
@@ -310,10 +325,13 @@ export function formatCurrency(
         : amount;
       // Round off to number of significant figures without trailing 0's
       return `${parseFloat(raw_amount).toPrecision(noDecimal.significantFigures) / 1}`;
-    } else if (
-      noDecimal.hasOwnProperty("decimalPlaces") &&
-      noDecimal.hasOwnProperty("significantFigures")
-    ) {
+    }
+
+    if (noDecimal.hasOwnProperty("maximumTrailingDecimalZeroes")) {
+      maximumTrailingDecimalZeroes = noDecimal.maximumTrailingDecimalZeroes;
+    }
+
+    if (noDecimal.hasOwnProperty("decimalPlaces") && noDecimal.hasOwnProperty("significantFigures")) {
       // Show specified number of significant digits with cutoff of specified fraction digits
       const currencyFormatterCustom = generateFormatter(
         isoCode,
@@ -326,9 +344,10 @@ export function formatCurrency(
         currencyFormatterCustom.format(
           Number.parseFloat(amount.toFixed(noDecimal.decimalPlaces))
         ),
-        locale
+        locale,
+        maximumTrailingDecimalZeroes
       );
-    } else {
+    } else if (noDecimal.hasOwnProperty("decimalPlaces") || noDecimal.hasOwnProperty("significantFigures")) {
       const currencyFormatterCustom = generateFormatter(
         isoCode,
         locale,
@@ -338,7 +357,8 @@ export function formatCurrency(
 
       return formatCurrencyOverride(
         currencyFormatterCustom.format(amount),
-        locale
+        locale,
+        maximumTrailingDecimalZeroes
       );
     }
   }