Add _.upperFirst and _.lowerFirst.

lodash.js

@@ -1446,14 +1446,14 @@
      * `isInteger`, `isMatch`, `isMatchWith`, `isNaN`, `isNative`, `isNil`, `isNull`,
      * `isNumber`, `isObject`, `isObjectLike`, `isPlainObject`, `isRegExp`,
      * `isSafeInteger`, `isString`, `isUndefined`, `isTypedArray`, `join`, `kebabCase`,
-     * `last`, `lastIndexOf`, `lowerCase`, `lt`, `lte`, `max`, `min`, `noConflict`,
-     * `noop`, `now`, `pad`, `padLeft`, `padRight`, `parseInt`, `pop`, `random`,
-     * `reduce`, `reduceRight`, `repeat`, `result`, `round`, `runInContext`,
+     * `last`, `lastIndexOf`, `lowerCase`, `lowerFirst`, `lt`, `lte`, `max`, `min`,
+     * `noConflict`, `noop`, `now`, `pad`, `padLeft`, `padRight`, `parseInt`, `pop`,
+     * `random`, `reduce`, `reduceRight`, `repeat`, `result`, `round`, `runInContext`,
      * `sample`, `shift`, `size`, `snakeCase`, `some`, `sortedIndex`, `sortedIndexBy`,
      * `sortedLastIndex`, `sortedLastIndexBy`, `startCase`, `startsWith`, `sum`,
      * `sumBy`, `template`, `toLower`, `toInteger`, `toString`, `toUpper`, `trim`,
      * `trimLeft`, `trimRight`, `trunc`, `unescape`, `uniqueId`, `upperCase`,
-     * `value`, and `words`
+     * `upperFirst`, `value`, and `words`
      *
      * @name _
      * @constructor
@@ -3769,6 +3769,25 @@
       return wrapper;
     }
 
+    /**
+     * Creates a function like `_.lowerFirst`.
+     *
+     * @private
+     * @param {string} methodName The name of the `String` case method to use.
+     * @returns {Function} Returns the new function.
+     */
+    function createCaseFirst(methodName) {
+      return function(string) {
+        string = toString(string);
+
+        var strSymbols = reHasComplexSymbol.test(string) ? stringToArray(string) : undefined,
+            chr = strSymbols ? strSymbols[0] : string.charAt(0),
+            trailing = strSymbols ? strSymbols.slice(1).join('') : string.slice(1);
+
+        return chr[methodName]() + trailing;
+      };
+    }
+
     /**
      * Creates a function like `_.camelCase`.
      *
@@ -11001,7 +11020,8 @@
     });
 
     /**
-     * Capitalizes the first character of `string`.
+     * Converts the first character of `string` to upper case and the remaining
+     * to lower case.
      *
      * @static
      * @memberOf _
@@ -11010,19 +11030,11 @@
      * @returns {string} Returns the capitalized string.
      * @example
      *
-     * _.capitalize('fred');
+     * _.capitalize('FRED');
      * // => 'Fred'
      */
     function capitalize(string) {
-      string = toString(string);
-      if (!string) {
-        return string;
-      }
-      if (reHasComplexSymbol.test(string)) {
-        var strSymbols = stringToArray(string);
-        return strSymbols[0].toUpperCase() + strSymbols.slice(1).join('');
-      }
-      return string.charAt(0).toUpperCase() + string.slice(1);
+      return upperFirst(toString(string).toLowerCase());
     }
 
     /**
@@ -11079,7 +11091,7 @@
     }
 
     /**
-     * Converts the characters "&", "<", ">", '"', "'", and "\`", in `string` to
+     * Converts the characters "&", "<", ">", '"', "'", and "\`" in `string` to
      * their corresponding HTML entities.
      *
      * **Note:** No other characters are escaped. To escape additional characters
@@ -11184,6 +11196,42 @@
       return result + (index ? ' ' : '') + word.toLowerCase();
     });
 
+    /**
+     * Converts the first character of `string` to lower case.
+     *
+     * @static
+     * @memberOf _
+     * @category String
+     * @param {string} [string=''] The string to convert.
+     * @returns {string} Returns the converted string.
+     * @example
+     *
+     * _.lowerFirst('Fred');
+     * // => 'fred'
+     *
+     * _.lowerFirst('FRED');
+     * // => 'fRED'
+     */
+    var lowerFirst = createCaseFirst('toLowerCase');
+
+    /**
+     * Converts the first character of `string` to upper case.
+     *
+     * @static
+     * @memberOf _
+     * @category String
+     * @param {string} [string=''] The string to convert.
+     * @returns {string} Returns the converted string.
+     * @example
+     *
+     * _.upperFirst('fred');
+     * // => 'Fred'
+     *
+     * _.upperFirst('FRED');
+     * // => 'FRED'
+     */
+    var upperFirst = createCaseFirst('toUpperCase');
+
     /**
      * Pads `string` on the left and right sides if it's shorter than `length`.
      * Padding characters are truncated if they can't be evenly divided by `length`.
@@ -12961,6 +13009,7 @@
     lodash.last = last;
     lodash.lastIndexOf = lastIndexOf;
     lodash.lowerCase = lowerCase;
+    lodash.lowerFirst = lowerFirst;
     lodash.lt = lt;
     lodash.lte = lte;
     lodash.max = max;
@@ -13007,6 +13056,7 @@
     lodash.unescape = unescape;
     lodash.uniqueId = uniqueId;
     lodash.upperCase = upperCase;
+    lodash.upperFirst = upperFirst;
 
     // Add aliases.
     lodash.first = head;

test/test.js

@@ -1757,8 +1757,7 @@
       assert.expect(1);
 
       var actual = _.map(strings, function(string) {
-        var expected = (caseName === 'start' && string === 'FOO BAR') ? string : converted;
-        return func(string) === expected;
+        return func(string) === converted;
       });
 
       assert.deepEqual(actual, _.map(strings, _.constant(true)));
@@ -1768,8 +1767,7 @@
       assert.expect(1);
 
       var actual = _.map(strings, function(string) {
-        var expected = (caseName === 'start' && string === 'FOO BAR') ? string : converted;
-        return func(func(string)) === expected;
+        return func(func(string)) === converted;
       });
 
       assert.deepEqual(actual, _.map(strings, _.constant(true)));
@@ -21272,6 +21270,7 @@
       'kebabCase',
       'last',
       'lowerCase',
+      'lowerFirst',
       'max',
       'maxBy',
       'min',
@@ -21303,7 +21302,8 @@
       'trimRight',
       'trunc',
       'unescape',
-      'upperCase'
+      'upperCase',
+      'upperFirst'
     ];
 
     _.each(funcs, function(methodName) {
@@ -21542,7 +21542,7 @@
     var acceptFalsey = _.difference(allMethods, rejectFalsey);
 
     QUnit.test('should accept falsey arguments', function(assert) {
-      assert.expect(257);
+      assert.expect(259);
 
       var emptyArrays = _.map(falsey, _.constant([]));