[core] Add number-format expression

1 files changed, 23 insertions, 0 deletions

diff --git a/platform/darwin/src/string_nsstring.mm b/platform/darwin/src/string_nsstring.mm
index 08f9aeccef..096ed2b212 100644
--- a/platform/darwin/src/string_nsstring.mm
+++ b/platform/darwin/src/string_nsstring.mm
@@ -27,5 +27,28 @@ std::string lowercase(const std::string &string) {
     return result;
 }
 
+std::string formatNumber(double number, const std::string& localeId, const std::string& currency,
+                         uint8_t minFractionDigits, uint8_t maxFractionDigits) {
+
+    static NSNumberFormatter *numberFormatter;
+    static dispatch_once_t onceToken;
+    dispatch_once(&onceToken, ^{
+        numberFormatter = [[NSNumberFormatter alloc] init];
+    });
+
+    numberFormatter.locale = !localeId.empty() ? [NSLocale localeWithLocaleIdentifier:@(localeId.c_str())] : nil;
+    numberFormatter.currencyCode = !currency.empty() ? @(currency.c_str()) : nil;
+    if (currency.empty()) {
+        numberFormatter.minimumFractionDigits = minFractionDigits;
+        numberFormatter.maximumFractionDigits = maxFractionDigits;
+        numberFormatter.numberStyle = NSNumberFormatterDecimalStyle;
+    } else {
+        numberFormatter.numberStyle = NSNumberFormatterCurrencyStyle;
+    }
+    NSString *formatted = [numberFormatter stringFromNumber:@(number)];
+    std::string result = std::string([formatted UTF8String]);
+    return result;
+}
+
 }
 }