lodash: added _.mapKeys() method

lodash/lodash-tests.ts

@@ -1794,6 +1794,54 @@ result = <string[]>_({ 'one': 1, 'two': 2, 'three': 3 }).keys().value();
 result = <string[]>_.keysIn({ 'one': 1, 'two': 2, 'three': 3 });
 result = <string[]>_({ 'one': 1, 'two': 2, 'three': 3 }).keysIn().value();
 
+// _.mapKeys
+module TestMapKeys {
+    let array: TResult[];
+    let list: _.List<TResult>;
+    let dictionary: _.Dictionary<TResult>;
+
+    let listIterator: (value: TResult, index: number, collection: _.List<TResult>) => string;
+    let dictionaryIterator: (value: TResult, key: string, collection: _.Dictionary<TResult>) => string;
+
+    let result: _.Dictionary<TResult>;
+
+    result = _.mapKeys<TResult, string>(array);
+    result = _.mapKeys<TResult, string>(array, listIterator);
+    result = _.mapKeys<TResult, string>(array, listIterator, any);
+    result = _.mapKeys<TResult>(array, '');
+    result = _.mapKeys<TResult, {}>(array, {});
+
+    result = _.mapKeys<TResult, string>(list);
+    result = _.mapKeys<TResult, string>(list, listIterator);
+    result = _.mapKeys<TResult, string>(list, listIterator, any);
+    result = _.mapKeys<TResult>(list, '');
+    result = _.mapKeys<TResult, {}>(list, {});
+
+    result = _.mapKeys<TResult, string>(dictionary);
+    result = _.mapKeys<TResult, string>(dictionary, dictionaryIterator);
+    result = _.mapKeys<TResult, string>(dictionary, dictionaryIterator, any);
+    result = _.mapKeys<TResult>(dictionary, '');
+    result = _.mapKeys<TResult, {}>(dictionary, {});
+
+    result = _(array).mapKeys<string>().value();
+    result = _(array).mapKeys<string>(listIterator).value();
+    result = _(array).mapKeys<string>(listIterator, any).value();
+    result = _(array).mapKeys('').value();
+    result = _(array).mapKeys<{}>({}).value();
+
+    result = _(list).mapKeys<TResult, string>().value();
+    result = _(list).mapKeys<TResult, string>(listIterator).value();
+    result = _(list).mapKeys<TResult, string>(listIterator, any).value();
+    result = _(list).mapKeys<TResult>('').value();
+    result = _(list).mapKeys<TResult, {}>({}).value();
+
+    result = _(dictionary).mapKeys<TResult, string>().value();
+    result = _(dictionary).mapKeys<TResult, string>(dictionaryIterator).value();
+    result = _(dictionary).mapKeys<TResult, string>(dictionaryIterator, any).value();
+    result = _(dictionary).mapKeys<TResult>('').value();
+    result = _(dictionary).mapKeys<TResult, {}>({}).value();
+}
+
 var mergeNames = {
     'stooges': [
         { 'name': 'moe' },

lodash/lodash.d.ts

@@ -7403,6 +7403,97 @@ declare module _ {
         keysIn(): LoDashArrayWrapper<string>
     }
 
+    //_.mapKeys
+    interface LoDashStatic {
+        /**
+         * The opposite of _.mapValues; this method creates an object with the same values as object and keys generated
+         * by running each own enumerable property of object through iteratee.
+         *
+         * @param object The object to iterate over.
+         * @param iteratee The function invoked per iteration.
+         * @param thisArg The this binding of iteratee.
+         * @return Returns the new mapped object.
+         */
+        mapKeys<T, TKey>(
+            object: List<T>,
+            iteratee?: ListIterator<T, TKey>,
+            thisArg?: any
+        ): Dictionary<T>;
+
+        /**
+         * @see _.mapKeys
+         */
+        mapKeys<T, TKey>(
+            object: Dictionary<T>,
+            iteratee?: DictionaryIterator<T, TKey>,
+            thisArg?: any
+        ): Dictionary<T>;
+
+        /**
+         * @see _.mapKeys
+         */
+        mapKeys<T, TObject extends {}>(
+            object: List<T>|Dictionary<T>,
+            iteratee?: TObject
+        ): Dictionary<T>;
+
+        /**
+         * @see _.mapKeys
+         */
+        mapKeys<T>(
+            object: List<T>|Dictionary<T>,
+            iteratee?: string
+        ): Dictionary<T>;
+    }
+
+    interface LoDashArrayWrapper<T> {
+        /**
+         * @see _.mapKeys
+         */
+        mapKeys<TKey>(
+            iteratee?: ListIterator<T, TKey>,
+            thisArg?: any
+        ): LoDashObjectWrapper<Dictionary<T>>;
+
+        /**
+         * @see _.mapKeys
+         */
+        mapKeys<TObject extends {}>(
+            iteratee?: TObject
+        ): LoDashObjectWrapper<Dictionary<T>>;
+
+        /**
+         * @see _.mapKeys
+         */
+        mapKeys(
+            iteratee?: string
+        ): LoDashObjectWrapper<Dictionary<T>>;
+    }
+
+    interface LoDashObjectWrapper<T> {
+        /**
+         * @see _.mapKeys
+         */
+        mapKeys<TResult, TKey>(
+            iteratee?: ListIterator<TResult, TKey>|DictionaryIterator<TResult, TKey>,
+            thisArg?: any
+        ): LoDashObjectWrapper<Dictionary<TResult>>;
+
+        /**
+         * @see _.mapKeys
+         */
+        mapKeys<TResult, TObject extends {}>(
+            iteratee?: TObject
+        ): LoDashObjectWrapper<Dictionary<TResult>>;
+
+        /**
+         * @see _.mapKeys
+         */
+        mapKeys<TResult>(
+            iteratee?: string
+        ): LoDashObjectWrapper<Dictionary<TResult>>;
+    }
+
     //_.mapValues
     interface LoDashStatic {
         /**