(feature) Add _.isLength

lodash/lodash-tests.ts

@@ -6055,6 +6055,27 @@ module TestIsInteger {
     }
 }
 
+// _.isLength
+module TestIsLength {
+    {
+        let result: boolean;
+
+        result = _.isLength(any);
+
+        result = _(1).isLength();
+        result = _<any>([]).isLength();
+        result = _({}).isLength();
+    }
+
+    {
+        let result: _.LoDashExplicitWrapper<boolean>;
+
+        result = _(1).chain().isLength();
+        result = _<any>([]).chain().isLength();
+        result = _({}).chain().isLength();
+    }
+}
+
 // _.isMatch
 var testIsMatchCustiomizerFn: (value: any, other: any, indexOrKey: number|string) => boolean;
 result = <boolean>_.isMatch({}, {});

lodash/lodash.d.ts

@@ -9791,6 +9791,49 @@ declare module _ {
         isInteger(): LoDashExplicitWrapper<boolean>;
     }
 
+    //_.isLength
+    interface LoDashStatic {
+        /**
+         * Checks if `value` is a valid array-like length.
+         *
+         * **Note:** This function is loosely based on [`ToLength`](http://ecma-international.org/ecma-262/6.0/#sec-tolength).
+         *
+         * @static
+         * @memberOf _
+         * @category Lang
+         * @param {*} value The value to check.
+         * @returns {boolean} Returns `true` if `value` is a valid length, else `false`.
+         * @example
+         *
+         * _.isLength(3);
+         * // => true
+         *
+         * _.isLength(Number.MIN_VALUE);
+         * // => false
+         *
+         * _.isLength(Infinity);
+         * // => false
+         *
+         * _.isLength('3');
+         * // => false
+         */
+        isLength(value?: any): boolean;
+    }
+
+    interface LoDashImplicitWrapperBase<T, TWrapper> {
+        /**
+         * @see _.isLength
+         */
+        isLength(): boolean;
+    }
+
+    interface LoDashExplicitWrapperBase<T, TWrapper> {
+        /**
+         * @see _.isLength
+         */
+        isLength(): LoDashExplicitWrapper<boolean>;
+    }
+
     //_.isMatch
     interface isMatchCustomizer {
         (value: any, other: any, indexOrKey?: number|string): boolean;