ionic4&angular8+打包之後本地輕按兩下通路www/index.html空白報錯，隻有把www部署到web伺服器上才能正常通路。經過反複查閱資料，對比ionic3和ionic4工程配置(tsconfig.json)才發現，原來是使用了：ES6子產品！
報錯資訊：
Access to script at 'file:///C:/Users/Administrator/Desktop/www/runtime-es2015.847c257376eede5504e2.js' from origin 'null' has been blocked by CORS policy: Cross origin requests are only supported for protocol schemes: http, data, chrome, chrome-extension, https.
runtime-es2015.847c257376eede5504e2.js:1 Failed to load resource: net::ERR_FAILED
TypeScript 編譯選項：
https://www.tslang.cn/docs/handbook/compiler-options.html
tsconfig.json 配置對比：
//ionic3 tsconfig.json
{
"compilerOptions": {
"module": "es2015",
"target": "es5",
"lib": ["dom", "es2015"]
}
...
}
//ionic4 tsconfig.json
{
"compileOnSave": false,
"compilerOptions": {
"module": "esnext",
"target": "es2015",
"lib": ["es2018", "dom"]
}
...
}