diff --git a/packages/api/src/index.ts b/packages/api/src/index.ts
index 58a23905..e7ede333 100644
--- a/packages/api/src/index.ts
+++ b/packages/api/src/index.ts
@@ -1,5 +1,4 @@
-import '@ms/ployfill'
-
+/// <reference types='@ms/ployfill' />
 export * from './task'
 export * from './event'
 export * from './console'
diff --git a/packages/ployfill/package.json b/packages/ployfill/package.json
index 5ff5d363..e7da872b 100644
--- a/packages/ployfill/package.json
+++ b/packages/ployfill/package.json
@@ -17,7 +17,8 @@
         "test": "echo \"Error: run tests from root\" && exit 1"
     },
     "dependencies": {
-        "@ms/nashorn": "^0.1.0"
+        "@ms/nashorn": "^0.1.0",
+        "core-js": "^3.6.4"
     },
     "devDependencies": {
         "reflect-metadata": "^0.1.13",
diff --git a/packages/ployfill/src/es5-ext.ts b/packages/ployfill/src/es5-ext.ts
new file mode 100644
index 00000000..fb99fc91
--- /dev/null
+++ b/packages/ployfill/src/es5-ext.ts
@@ -0,0 +1,26 @@
+// ES2015 String ployfill must force overwrite to js method
+Object.defineProperty(String.prototype, 'contains', {
+    value: require(`es5-ext/string/#/contains/shim`),
+    configurable: true,
+    enumerable: false,
+    writable: true
+})
+Object.defineProperty(String.prototype, 'repeat', {
+    value: require(`es5-ext/string/#/repeat/shim`),
+    configurable: true,
+    enumerable: false,
+    writable: true
+})
+Object.defineProperty(String.prototype, 'startsWith', {
+    value: require(`es5-ext/string/#/starts-with/shim`),
+    configurable: true,
+    enumerable: false,
+    writable: true
+})
+Object.defineProperty(String.prototype, 'endsWith', {
+    value: require(`es5-ext/string/#/ends-with/shim`),
+    configurable: true,
+    enumerable: false,
+    writable: true
+})
+
diff --git a/packages/ployfill/src/index.ts b/packages/ployfill/src/index.ts
index 9d436f7a..4b7d07e7 100644
--- a/packages/ployfill/src/index.ts
+++ b/packages/ployfill/src/index.ts
@@ -1,19 +1,10 @@
-import './global'
-import '@ms/nashorn'
-import { Proxy } from './proxy'
-import { XMLHttpRequest } from './xml-http-request'
-
+/// <reference path="./global.ts" />
+/// <reference types='@ms/nashorn' />
 let ployfillStartTime = new Date().getTime();
 console.info('Initialization Java Nashorn ployfill. Please wait...');
-// String contains ployfill
-Object.defineProperty(String.prototype, 'contains', {
-    value: function(searchString: string, position: number) {
-        return String.prototype.indexOf.call(this, searchString, position) > -1;
-    }
-})
-// ES6 Map Symbol ployfill
-require('es6-map/implement');
-require('es6-symbol/implement');
-global.setGlobal('Proxy', Proxy)
-global.setGlobal('XMLHttpRequest', XMLHttpRequest)
+require('./es5-ext');
+require('core-js');
+global.setGlobal('Proxy', require('./proxy').Proxy)
+global.setGlobal('XMLHttpRequest', require('./xml-http-request').XMLHttpRequest)
+global.setGlobal('Blob', require('blob-polyfill').Blob)
 console.info('Java Nashorn ployfill loading completed... Cost (' + (new Date().getTime() - ployfillStartTime) / 1000 + 's)!');
diff --git a/packages/ployfill/src/proxy.ts b/packages/ployfill/src/proxy.ts
index d85e19cd..f7eb7558 100644
--- a/packages/ployfill/src/proxy.ts
+++ b/packages/ployfill/src/proxy.ts
@@ -1,3 +1,4 @@
+// Nashorn JSAdapter See https://wiki.openjdk.java.net/display/Nashorn/Nashorn+extensions#Nashornextensions-JSAdapterconstructor
 let createProxy = eval(`
     function(handle){ return new JSAdapter(handle) }
 `)
diff --git a/packages/plugins/src/MiaoChat.ts b/packages/plugins/src/MiaoChat.ts
index 419768a7..bfe65045 100644
--- a/packages/plugins/src/MiaoChat.ts
+++ b/packages/plugins/src/MiaoChat.ts
@@ -138,22 +138,6 @@ export class MiaoChat extends interfaces.Plugin {
     private PlaceholderAPI: { setPlaceholders: (player: any, str: string) => string };
 
     load() {
-        if (!Object.values) {
-            Object.defineProperty(Object, "values", {
-                enumerable: false,
-                configurable: true,
-                writable: true,
-                value: function(target) {
-                    "use strict";
-                    var values = [];
-                    for (var key in target) {
-                        var desc = Object.getOwnPropertyDescriptor(target, key);
-                        if (desc !== undefined && desc.enumerable) values.push(target[key]);
-                    }
-                    return values;
-                }
-            });
-        }
         this.chatFormats = Object.values(this.config.ChatFormats);
         this.chatFormats.sort(this.compare('index'));
         this.initFormat(this.chatFormats);