lodash: added _.update

lodash/lodash-tests.ts

@@ -9619,6 +9619,51 @@ namespace TestUnset {
     }
 }
 
+// _.update
+namespace TestUpdate {
+    type SampleObject = {a: {}};
+    type SampleResult = {a: {b: number[]}};
+
+    let object: SampleObject;
+    let updater: (value: any) => number;
+
+    {
+        let result: SampleResult;
+
+        result = _.update<SampleResult>(object, 'a.b[1]', updater);
+        result = _.update<SampleResult>(object, ['a', 'b', 1], updater);
+
+        result = _.update<(value: any) => number, SampleResult>(object, 'a.b[1]', updater);
+        result = _.update<(value: any) => number, SampleResult>(object, ['a', 'b', 1], updater);
+
+        result = _.update<SampleObject, SampleResult>(object, 'a.b[1]', updater);
+        result = _.update<SampleObject, SampleResult>(object, ['a', 'b', 1], updater);
+
+        result = _.update<SampleObject, (value: any) => number, SampleResult>(object, 'a.b[1]', updater);
+        result = _.update<SampleObject, (value: any) => number, SampleResult>(object, ['a', 'b', 1], updater);
+    }
+
+    {
+        let result: _.LoDashImplicitObjectWrapper<SampleResult>;
+
+        result = _(object).update<SampleResult>('a.b[1]', updater);
+        result = _(object).update<SampleResult>(['a', 'b', 1], updater);
+
+        result = _(object).update<(value: any) => number, SampleResult>('a.b[1]', updater);
+        result = _(object).update<(value: any) => number, SampleResult>(['a', 'b', 1], updater);
+    }
+
+    {
+        let result: _.LoDashExplicitObjectWrapper<SampleResult>;
+
+        result = _(object).chain().update<SampleResult>('a.b[1]', updater);
+        result = _(object).chain().update<SampleResult>(['a', 'b', 1], updater);
+
+        result = _(object).chain().update<(value: any) => number, SampleResult>('a.b[1]', updater);
+        result = _(object).chain().update<(value: any) => number, SampleResult>(['a', 'b', 1], updater);
+    }
+}
+
 // _.values
 module TestValues {
     let object: _.Dictionary<TResult>;

lodash/lodash.d.ts

@@ -16216,6 +16216,87 @@ declare module _ {
         unset(path: StringRepresentable|StringRepresentable[]): LoDashExplicitWrapper<boolean>;
     }
 
+    //_.update
+    interface LoDashStatic {
+        /**
+         * This method is like _.set except that accepts updater to produce the value to set. Use _.updateWith to
+         * customize path creation. The updater is invoked with one argument: (value).
+         *
+         * @param object The object to modify.
+         * @param path The path of the property to set.
+         * @param updater The function to produce the updated value.
+         * @return Returns object.
+         */
+        update<TResult>(
+            object: Object,
+            path: StringRepresentable|StringRepresentable[],
+            updater: Function
+        ): TResult;
+
+        /**
+         * @see _.update
+         */
+        update<U extends Function, TResult>(
+            object: Object,
+            path: StringRepresentable|StringRepresentable[],
+            updater: U
+        ): TResult;
+
+        /**
+         * @see _.update
+         */
+        update<O extends {}, TResult>(
+            object: O,
+            path: StringRepresentable|StringRepresentable[],
+            updater: Function
+        ): TResult;
+
+        /**
+         * @see _.update
+         */
+        update<O, U extends Function, TResult>(
+            object: O,
+            path: StringRepresentable|StringRepresentable[],
+            updater: U
+        ): TResult;
+    }
+
+    interface LoDashImplicitObjectWrapper<T> {
+        /**
+         * @see _.update
+         */
+        update<TResult>(
+            path: StringRepresentable|StringRepresentable[],
+            updater: any
+        ): LoDashImplicitObjectWrapper<TResult>;
+
+        /**
+         * @see _.update
+         */
+        update<U extends Function, TResult>(
+            path: StringRepresentable|StringRepresentable[],
+            updater: U
+        ): LoDashImplicitObjectWrapper<TResult>;
+    }
+
+    interface LoDashExplicitObjectWrapper<T> {
+        /**
+         * @see _.update
+         */
+        update<TResult>(
+            path: StringRepresentable|StringRepresentable[],
+            updater: any
+        ): LoDashExplicitObjectWrapper<TResult>;
+
+        /**
+         * @see _.update
+         */
+        update<U extends Function, TResult>(
+            path: StringRepresentable|StringRepresentable[],
+            updater: U
+        ): LoDashExplicitObjectWrapper<TResult>;
+    }
+
     //_.values
     interface LoDashStatic {
         /**