Split index.js to separate files (#17315)

* split `index.js` to separate files

* tune clipboard

* fix promise

* fix document

* remove intermediate empty file

* fix async event listener

* use `export function` instead of `export {}`, add more comments

Co-authored-by: Lunny Xiao <xiaolunwen@gmail.com>
Co-authored-by: 6543 <6543@obermui.de>

web_src/js/components/VueComponentLoader.js

@@ -1,10 +1,10 @@
 import Vue from 'vue';
 import {svgs} from '../svg.js';
 
-const vueDelimiters = ['${', '}'];
+export const vueDelimiters = ['${', '}'];
 
 let vueEnvInited = false;
-function initVueEnv() {
+export function initVueEnv() {
   if (vueEnvInited) return;
   vueEnvInited = true;
 
@@ -14,7 +14,7 @@ function initVueEnv() {
 }
 
 let vueSvgInited = false;
-function initVueSvg() {
+export function initVueSvg() {
   if (vueSvgInited) return;
   vueSvgInited = true;
 
@@ -36,8 +36,7 @@ function initVueSvg() {
   }
 }
 
-
-function initVueApp(el, opts = {}) {
+export function initVueApp(el, opts = {}) {
   if (typeof el === 'string') {
     el = document.querySelector(el);
   }
@@ -48,5 +47,3 @@ function initVueApp(el, opts = {}) {
     delimiters: vueDelimiters,
   }, opts));
 }
-
-export {vueDelimiters, initVueEnv, initVueSvg, initVueApp};