perf[Tinymce]: dynamic import tinymce(#2102)

src/components/Tinymce/dynamicLoadScript.js

@@ -0,0 +1,39 @@
+const dynamicLoadScript = (src, callback) => {
+  const existingScript = document.getElementById(src)
+  const cb = callback || function() {}
+
+  if (!existingScript) {
+    const script = document.createElement('script')
+    script.src = src // src url for the third-party library being loaded.
+    script.id = src
+    document.body.appendChild(script)
+
+    const onEnd = 'onload' in script ? stdOnEnd : ieOnEnd
+    onEnd(script, cb)
+  }
+
+  if (existingScript && cb) cb(null, existingScript)
+
+  function stdOnEnd(script, cb) {
+    script.onload = function() {
+      // this.onload = null here is necessary
+      // because even IE9 works not like others
+      this.onerror = this.onload = null
+      cb(null, script)
+    }
+    script.onerror = function() {
+      this.onerror = this.onload = null
+      cb(new Error('Failed to load ' + src), script)
+    }
+  }
+
+  function ieOnEnd(script, cb) {
+    script.onreadystatechange = function() {
+      if (this.readyState !== 'complete' && this.readyState !== 'loaded') return
+      this.onreadystatechange = null
+      cb(null, script) // there is no way to catch loading errors in IE8
+    }
+  }
+}
+
+export default dynamicLoadScript