Create type definition for 'nested-property' (#4004)

* Create type definition for 'nested-property'

* Follow lint

src/@types/nested-property.d.ts

@@ -0,0 +1,19 @@
+declare module 'nested-property' {
+	interface IHasNestedPropertyOptions {
+		own?: boolean;
+	}
+
+	interface IIsInNestedPropertyOptions {
+		validPath?: boolean;
+	}
+
+	export function set<T>(object: T, property: string, value: any): T;
+
+	export function get(object: object, property: string): any;
+
+	export function has(object: object, property: string, options?: IHasNestedPropertyOptions): boolean;
+
+	export function hasOwn(object: object, property: string, options?: IHasNestedPropertyOptions): boolean;
+
+	export function isIn(object: object, property: string, objectInPath: object, options?: IIsInNestedPropertyOptions): boolean;
+}

src/chart/index.ts

@@ -3,7 +3,7 @@
  */
 
 import * as moment from 'moment';
-const nestedProperty = require('nested-property');
+import * as nestedProperty from 'nested-property';
 import autobind from 'autobind-decorator';
 import * as mongo from 'mongodb';
 import db from '../db/mongodb';

src/server/web/docs.ts

@@ -17,7 +17,7 @@ import { licenseHtml } from '../../misc/license';
 const constants = require('../../const.json');
 import endpoints from '../api/endpoints';
 const locales = require('../../../locales');
-const nestedProperty = require('nested-property');
+import * as nestedProperty from 'nested-property';
 
 async function genVars(lang: string): Promise<{ [key: string]: any }> {
 	const vars = {} as { [key: string]: any };