fixed float formatting for js

lib/pure/strutils.nim

@@ -1344,8 +1344,8 @@ proc editDistance*(a, b: string): int {.noSideEffect,
 
 
 # floating point formating:
-
-proc c_sprintf(buf, frmt: cstring): cint {.header: "<stdio.h>",
+when not defined(js):
+  proc c_sprintf(buf, frmt: cstring): cint {.header: "<stdio.h>",
                                      importc: "sprintf", varargs, noSideEffect.}
 
 type
@@ -1370,6 +1370,21 @@ proc formatBiggestFloat*(f: BiggestFloat, format: FloatFormatMode = ffDefault,
   ## after the decimal point for Nim's ``biggestFloat`` type.
   ##
   ## If ``precision == 0``, it tries to format it nicely.
+  when defined(js):
+    var res: cstring
+    case format
+    of ffDefault:
+      {.emit: "`res` = `f`.toString();".}
+    of ffDecimal:
+      {.emit: "`res` = `f`.toFixed(`precision`);".}
+    of ffScientific:
+      {.emit: "`res` = `f`.toExponential(`precision`);".}
+    result = $res
+    for i in 0 ..< result.len:
+      # Depending on the locale either dot or comma is produced,
+      # but nothing else is possible:
+      if result[i] in {'.', ','}: result[i] = decimalsep
+  else:
     const floatFormatToChar: array[FloatFormatMode, char] = ['g', 'f', 'e']
     var
       frmtstr {.noinit.}: array[0..5, char]

tests/testament/categories.nim

@@ -223,6 +223,9 @@ proc jsTests(r: var TResults, cat: Category, options: string) =
                    "varres/tvartup"]:
     test "tests/" & testfile & ".nim"
 
+  for testfile in ["pure/strutils"]:
+    test "lib/" & testfile & ".nim"
+
 # ------------------------- manyloc -------------------------------------------
 #proc runSpecialTests(r: var TResults, options: string) =
 #  for t in ["lib/packages/docutils/highlite"]: