Uncaught SyntaxError：较旧的android版本上的意外保留字

Question

I am programming an app using cordova and testing it on android 8.0.0 it works fine. But on my friend's phone (android 4.4.4) it does not work, I got these errors in the console log.

Uncaught SyntaxError: Unexpected reserved word Widget.js:9
Uncaught SyntaxError: Unexpected reserved word Image.js:8
Uncaught SyntaxError: <unknown message reserved_word> Button.js:7
Uncaught SyntaxError: <unknown message reserved_word> TextArea.js:8
Uncaught SyntaxError: <unknown message reserved_word> Effect.js:8
Uncaught SyntaxError: Unexpected reserved word View.js:9
Uncaught SyntaxError: <unknown message reserved_word> User_interface.js:8
Uncaught SyntaxError: <unknown message reserved_word> Communication.js:8
Uncaught SyntaxError: <unknown message reserved_word> App.js:7

Those errors block on the keyword "class"

Uncaught SyntaxError: Unexpected token ) index.js:16

and also block on :

AndroidFullScreen.immersiveMode(()=>{},()=>{});

Here I think it doesn't recognize the arrow function but i'm not sure.

I would like to know if I can fix it or the phone is just too old for my app? If you need other information tell me and I will provide them :)

Thanks in advance

Answer 1

Before Android 4.4 cordova was using the old android browser (very old support of html 5).

Starting from android 4.4 the android browser was replaced by Chrome but the version of Chrome used by the webview couldn't be upgraded (version 36 for 4.4).

Since android 5.0, chrome is now in an apk and can be updated.

Arrow functions require a minimum Chrome version of 45, that's why your app doesn't work correctly on your friend's phone.

If want your app to work correctly of phones older than android 5, you can either:

• not use too recent javasctipt (check support on caniuse)
• use the crosswalk plugin to embed the webview in your app

Crosswalk was supposed to always use the latest version of chromium but unfortunatly the project is no more updated so you will not be able to use the latest javascript updates either. (latest version of Crosswalk uses chromium version 53 wich is much more recent than the 36 used in android 4.4)

The advantage of Crosswaalk is that your app has the same support of html/js/css on all device so you know how your app will behave/look like on all devices.

Using Crosswalk will lead to a much bigger APK so that's not always the best option.

You could also build two different apk versions, one for android <5.0 and one for newer.

Answer 2

您是否知道有人偶然将原始和更新的铬分叉到55或更高？