refactor(assign): add Object.assign polyfill util

src/util/assign.ts

@@ -0,0 +1,30 @@
+import {root} from './root';
+
+const Object = root.Object;
+
+if (typeof (<any>Object).assign != 'function') {
+ (function () {
+ (<any>Object).assign = function assignPolyfill(target: Object, ...sources: Array<Object>): Object {
+ if (target === undefined || target === null) {
+ throw new TypeError('Cannot convert undefined or null to object');
+ }
+
+ const output = Object(target);
+ const len = sources.length;
+ for (let index = 0; index < len; index++) {
+ let source = sources[index];
+ if (source !== undefined && source !== null) {
+ for (let key in source) {
+ if (source.hasOwnProperty(key)) {
+ output[key] = source[key];
+ }
+ }
+ }
+ }
+
+ return output;
+ };
+ })();
+}
+
+export const assign: (target: Object, ...sources: Array<Object>) => Object = Object.assign;