Why is WInJS included automatically when targeting Windows 8 in Cordova?

问题

We're developing an app using AngularJS, and when we're targeting Windows 8 I noticed that the generated Visual Studio project included WinJS as a reference. Since we're not using WinJS I simply removed the reference from the project.

Then I noticed that removing WinJS caused benign script load errors in the console when running the app. Further investigation showed that cordova.js automatically checks for WinJS, and if not included tries to include it (!). Here's the relevant code:

var onWinJSReady = function () {
    var app = WinJS.Application;
    var checkpointHandler = function checkpointHandler() {
        cordova.fireDocumentEvent('pause',null,true);
    };

    var resumingHandler = function resumingHandler() {
        cordova.fireDocumentEvent('resume',null,true);
    };

    app.addEventListener("checkpoint", checkpointHandler);
    Windows.UI.WebUI.WebUIApplication.addEventListener("resuming", resumingHandler, false);
    app.start();
};

if (!window.WinJS) {
    var scriptElem = document.createElement("script");

    if (navigator.appVersion.indexOf("Windows Phone 8.1;") !== -1) {
        // windows phone 8.1 + Mobile IE 11
        scriptElem.src = "//Microsoft.Phone.WinJS.2.1/js/base.js";
    } else if (navigator.appVersion.indexOf("MSAppHost/2.0;") !== -1) {
        // windows 8.1 + IE 11
        scriptElem.src = "//Microsoft.WinJS.2.0/js/base.js";
    } else {
        // windows 8.0 + IE 10
        scriptElem.src = "//Microsoft.WinJS.1.0/js/base.js";
    }
    scriptElem.addEventListener("load", onWinJSReady);
    document.head.appendChild(scriptElem);
}
else {
    onWinJSReady();
}

I guess my main question is, should I just leave the WinJS reference "as is" and let Cordova load and initialize WinJS?

Could it potentially conflict with AngularJS or reduce the performance of the app in any way? (I guess var app = WinJS.Application and app.start() in onWinJSReady makes me a bit worried).

Since the app seems to work fine without the WinJS script files, why is cordova.js so insistent on trying to include it?

回答1:

cordova (and some cordova plugins, particularly the FileSystem plugin) use some features of WinJS, such as Promises and Ajax calls. We ended up forking cordova.js and stripping out all the WinJS stuff... makes the app load a lot faster!

来源：https://stackoverflow.com/questions/28233531/why-is-winjs-included-automatically-when-targeting-windows-8-in-cordova

标签

javascript

angularjs

cordova

winjs