refactor: use ES6 construct instead of object-assign

BREAKING CHANGE: `object-assign` dependency is replaced by `tslib`

Author: bhovhannes

package.json

@@ -18,7 +18,7 @@
     "es6-promise": "4.2.4",
     "form-data": "2.3.2",
     "isomorphic-fetch": "2.2.1",
-    "object-assign": "4.1.1",
+    "tslib": "1.9.2",
     "workfront-api-constants": "2.0.0"
   },
   "devDependencies": {
@@ -47,7 +47,6 @@
     "semver": "5.5.0",
     "should": "13.2.1",
     "ts-loader": "4.3.1",
-    "tslib": "1.9.2",
     "tslint": "5.10.0",
     "tslint-config-prettier": "1.13.0",
     "tslint-loader": "3.6.0",

src/Api.ts

@@ -21,7 +21,6 @@
 
 import * as NodeFormData from 'form-data'
 import 'isomorphic-fetch'
-import * as objectAssign from 'object-assign'
 import {Readable} from 'stream'
 import {INTERNAL_PREFIX} from 'workfront-api-constants'
 
@@ -261,7 +260,7 @@ export class Api {
             params.action = action
         }
         if (actionArgs) {
-            params = objectAssign(params, actionArgs)
+            params = {...params, ...actionArgs}
         }
         return this.request(endPoint, params, null, Api.Methods.POST)
     }
@@ -415,11 +414,11 @@ export class Api {
         fields?: TFields,
         method: string = Api.Methods.GET
     ): Promise<any> {
-        const clonedParams = objectAssign({}, params)
+        const clonedParams = {...params}
 
         const alwaysUseGet = this._httpOptions.alwaysUseGet
 
-        const options = objectAssign({}, this._httpOptions)
+        const options = {...this._httpOptions}
         if (alwaysUseGet && path !== 'login') {
             clonedParams.method = method
             options.method = Api.Methods.GET
@@ -512,7 +511,7 @@ export class Api {
     search(objCode: string, query?: object, fields?: TFields, useHttpPost = false) {
         let searchQuery, method
         if (useHttpPost) {
-            searchQuery = objectAssign({}, query, {method: Api.Methods.GET})
+            searchQuery = {...query, method: Api.Methods.GET}
             method = Api.Methods.POST
         } else {
             searchQuery = query

tslint.json

@@ -6,10 +6,6 @@
     "member-access": false,
     "no-string-literal": false,
     "no-var-requires": false,
-    "object-literal-key-quotes": [
-      true,
-      "as-needed"
-    ],
     "object-literal-shorthand": false,
     "object-literal-sort-keys": false,
     "one-variable-per-declaration": false,

webpack.config.js

@@ -7,6 +7,7 @@ module.exports = {
     entry: {
 		'./dist/workfront': './src/Api.ts'
     },
+    mode: 'development',
     output: {
         path: __dirname,
         filename: '[name].js',