Add _.inRange.

lodash.src.js

@@ -9562,6 +9562,48 @@
 
     /*------------------------------------------------------------------------*/
 
+    /**
+     * Checks if `n` is between `start` and up to but not including, `end`. If
+     * `end` is not specified it defaults to `start` with `start` becoming `0`.
+     *
+     * @static
+     * @memberOf _
+     * @category Number
+     * @param {number} n The number to check.
+     * @param {number} [start=0] The start of the range.
+     * @param {number} end The end of the range.
+     * @returns {boolean} Returns `true` if `n` is in the range, else `false`.
+     * @example
+     *
+     * _.inRange(3, 2, 4);
+     * // => true
+     *
+     * _.inRange(4, 8);
+     * // => true
+     *
+     * _.inRange(4, 2);
+     * // => false
+     *
+     * _.inRange(2, 2);
+     * // => false
+     *
+     * _.inRange(1.2, 2);
+     * // => true
+     *
+     * _.inRange(5.2, 4);
+     * // => false
+     */
+    function inRange(value, start, end) {
+      start = +start || 0;
+      if (typeof end === 'undefined') {
+        end = start;
+        start = 0;
+      } else {
+        end = +end || 0;
+      }
+      return value >= start && value < end;
+    }
+
     /**
      * Produces a random number between `min` and `max` (inclusive). If only one
      * argument is provided a number between `0` and the given number is returned.
@@ -10845,8 +10887,9 @@
 
     /**
      * Creates an array of numbers (positive and/or negative) progressing from
-     * `start` up to, but not including, `end`. If `start` is less than `end` a
-     * zero-length range is created unless a negative `step` is specified.
+     * `start` up to, but not including, `end`. If `end` is not specified it
+     * defaults to `start` with `start` becoming `0`. If `start` is less than
+     * `end` a zero-length range is created unless a negative `step` is specified.
      *
      * @static
      * @memberOf _
@@ -11131,6 +11174,7 @@
     lodash.identity = identity;
     lodash.includes = includes;
     lodash.indexOf = indexOf;
+    lodash.inRange = inRange;
     lodash.isArguments = isArguments;
     lodash.isArray = isArray;
     lodash.isBoolean = isBoolean;

test/test.js

@@ -6091,6 +6091,50 @@
 
   /*--------------------------------------------------------------------------*/
 
+  QUnit.module('lodash.inRange');
+
+  (function() {
+    test('should work with an `end` argument', 3, function() {
+      strictEqual(_.inRange(3, 5), true);
+      strictEqual(_.inRange(5, 5), false);
+      strictEqual(_.inRange(6, 5), false);
+    });
+
+    test('should work with `start` and `end` arguments', 4, function() {
+      strictEqual(_.inRange(1, 1, 5), true);
+      strictEqual(_.inRange(3, 1, 5), true);
+      strictEqual(_.inRange(0, 1, 5), false);
+      strictEqual(_.inRange(5, 1, 5), false);
+    });
+
+    test('should treat falsey `start` arguments as `0`', 13, function() {
+      _.each(falsey, function(value, index) {
+        if (index) {
+          strictEqual(_.inRange(0, value), false);
+          strictEqual(_.inRange(0, value, 1), true);
+        } else {
+          strictEqual(_.inRange(0), false);
+        }
+      });
+    });
+
+    test('should work with a floating point `n` value', 4, function() {
+      strictEqual(_.inRange(0.5, 5), true);
+      strictEqual(_.inRange(1.2, 1, 5), true);
+      strictEqual(_.inRange(5.2, 5), false);
+      strictEqual(_.inRange(0.5, 1, 5), false);
+    });
+
+    test('should coerce arguments to finite numbers', 1, function() {
+      var actual = [_.inRange(0, '0', 1), _.inRange(0, '1'), _.inRange(0, 0, '1'), _.inRange(0, NaN, 1), _.inRange(-1, -1, NaN)],
+          expected = _.map(actual, _.constant(true));
+
+      deepEqual(actual, expected);
+    });
+  }());
+
+  /*--------------------------------------------------------------------------*/
+
   QUnit.module('lodash.intersection');
 
   (function() {
@@ -11178,7 +11222,7 @@
   QUnit.module('lodash.range');
 
   (function() {
-    test('should work with a single `end` argument', 1, function() {
+    test('should work with an `end` argument', 1, function() {
       deepEqual(_.range(4), [0, 1, 2, 3]);
     });
 
@@ -15482,7 +15526,7 @@
 
     var acceptFalsey = _.difference(allMethods, rejectFalsey);
 
-    test('should accept falsey arguments', 208, function() {
+    test('should accept falsey arguments', 209, function() {
       var emptyArrays = _.map(falsey, _.constant([])),
           isExposed = '_' in root,
           oldDash = root._;