simplify numberToIdentifer method

timse · timse · commit d74491d3f1fc · 2016-12-26T21:53:12.000+11:00
diff --git a/lib/Template.js b/lib/Template.js
@@ -20,16 +20,21 @@ Template.toIdentifier = function(str) {
 	return str.replace(/^[^a-zA-Z$_]/, "_").replace(/[^a-zA-Z0-9$_]/g, "_");
 };
 
-var A_CODE = "a".charCodeAt(0);
-var Z_CODE = "z".charCodeAt(0);
-var AZ_COUNT = Z_CODE - A_CODE + 1;
-var A2_CODE = "A".charCodeAt(0);
-var Z2_CODE = "Z".charCodeAt(0);
-var AZ2_COUNT = Z2_CODE - A2_CODE + 1;
+var START_LOWERCASE_ALPHABET_CODE = "a".charCodeAt(0);
+var START_UPPERCASE_ALPHABET_CODE = "A".charCodeAt(0);
+var DELTA_A_TO_Z = "z".charCodeAt(0) - START_LOWERCASE_ALPHABET_CODE + 1;
+// map number to a single character a-z, A-Z or <_ + number> if number is too big
 Template.numberToIdentifer = function numberToIdentifer(n) {
-	if(n < AZ_COUNT) return String.fromCharCode(A_CODE + n);
-	if(n < AZ_COUNT + AZ2_COUNT) return String.fromCharCode(A2_CODE + n - AZ_COUNT);
-	return "_" + (n - AZ_COUNT - AZ2_COUNT);
+	// lower case
+	if(n < DELTA_A_TO_Z) return String.fromCharCode(START_LOWERCASE_ALPHABET_CODE + n);
+
+	// upper case
+	n -= DELTA_A_TO_Z;
+	if(n < DELTA_A_TO_Z) return String.fromCharCode(START_UPPERCASE_ALPHABET_CODE + n);
+
+	// fall back to _ + number
+	n -= DELTA_A_TO_Z;
+	return "_" + n;
 };
 
 Template.prototype = Object.create(Tapable.prototype);
