Recognize half width characters

Shazzaam · Oct 15, 2015 · 1fc9a25 · 1fc9a25
1 parent abf3069
commit 1fc9a25
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Showing 2 changed files with 13 additions and 1 deletion.
diff --git a/spec/text-utils-spec.coffee b/spec/text-utils-spec.coffee
@@ -57,3 +57,10 @@ describe 'text utilities', ->
       expect(textUtils.isDoubleWidthCharacter("，")).toBe(true)
 
       expect(textUtils.isDoubleWidthCharacter("a")).toBe(false)
+
+  describe ".isHalfWidthCharacter(character)", ->
+    it "returns true when the character is an half width form", ->
+      expect(textUtils.isHalfWidthCharacter("ﾊ")).toBe(true)
+      expect(textUtils.isHalfWidthCharacter("ﾋ")).toBe(true)
+      expect(textUtils.isHalfWidthCharacter("ﾬ")).toBe(true)
+      expect(textUtils.isHalfWidthCharacter("B")).toBe(false)
diff --git a/src/text-utils.coffee b/src/text-utils.coffee
@@ -81,6 +81,11 @@ isDoubleWidthCharacter = (character) ->
   isCjkUnifiedIdeograph(charCode) or
   isFullWidthForm(charCode)
 
+isHalfWidthCharacter = (character) ->
+  charCode = character.charCodeAt(0)
+
+  0xFF65 <= charCode <= 0xFFDC
+
 # Does the given string contain at least surrogate pair, variation sequence,
 # or combined character?
 #
@@ -94,4 +99,4 @@ hasPairedCharacter = (string) ->
     index++
   false
 
-module.exports = {isPairedCharacter, hasPairedCharacter, isDoubleWidthCharacter}
+module.exports = {isPairedCharacter, hasPairedCharacter, isDoubleWidthCharacter, isHalfWidthCharacter}