feat(pwa): add sw.js

src/core/fetch/ajax.js

@@ -2,7 +2,6 @@ import progressbar from '../render/progressbar'
 import { noop } from '../util/core'
 
 const cache = {}
-const RUN_VERSION = Date.now()
 
 /**
  * Simple ajax get
@@ -16,8 +15,6 @@ export function get (url, hasBar = false) {
     xhr.addEventListener.apply(xhr, arguments)
   }
 
-  url += (/\?(\w+)=/g.test(url) ? '&' : '?') + `v=${RUN_VERSION}`
-
   if (cache[url]) {
     return { then: cb => cb(cache[url]), abort: noop }
   }