Detect JS failures on asset version changes

[neongreen]

Scenario:

• My app uses IHP 0.14
• User opens the app and keeps the tab open
• I upgrade to IHP 0.15 and deploy
• User performs any action in the open tab

In this scenario, JS asset versions will change and Turbolinks will attempt to load the new versions of all assets without unloading the old versions:

This will lead to silent errors like those:

Any behavior relying on custom JS will silently break.

I propose detecting this with window.onerror and doing a full page reload or.. something. Not sure what exactly should be done.

[neongreen]

My workaround has been to ask the user to reload the page manually:

// app.js

$(window).on("error", function(evt) {
    var e = evt.originalEvent; // get the javascript event
    if (e.message) { 
        alert("JavaScript error:\n    " + e.message + "\n" +
              "Line:\n    " + e.lineno + "\n" +
              "File:\n    " + e.filename + "\n\n" +
              "Please reload the page!");
    } else {
        alert("JavaScript error:\n    " + e.type + "\n" +
              "Element:\n    " + (e.srcElement || e.target) + "\n\n" +
              "Please reload the page!");
    }
});