有没有办法警告使用IE版本不支持的JavaScript功能？

Question

I am working in a shop that uses Typescript for most new development so we are very used to using ES6 features like arrow functions and have them made safe for Internet Explorer by the transpilation step. But this week I had to edit an existing js file (which has no transpilation) and stupidly used an arrow function. This worked fine in my modern development browsers, but broke in QA under IE 9.

So I know this is my dumb mistake, but I am wondering if there is tooling that can warn if features that do not meet a particular browser version are used to use as double check? If this has a Visual Studio integration that would be wonderful, but I have no problem adding a command line step to my work flow. I looked at ESHint but didn't see that sort of rule.

Answer 1

If you're just talking IE (I know nothing of Typescript) and Visual Studio, you can use the following in VS:

    WinPath = System.Environment.GetEnvironmentVariable("SystemRoot")   ''MsgBox(WinPath)

    On Error Resume Next

    Dim ver = FileVersionInfo.GetVersionInfo(WinPath & "\system32\ieframe.dll")
    Dim IE = Val(ver.ProductVersion) ''MsgBox(IE)

This will return the local machine IE version - is this what you want?

If not, Javascript can detect which browser it is being used by with this script:

var browser=navigator.userAgent;
var IE=browser.search(/(MSIE ?[7891]|Trident|Edge\/)/i);    //=-1: not MS
if (IE!=-1) {
    T=browser.substr(IE,7);
    if (T.search(/^M/)==0) IE=parseInt(T.substr(4));
    else if (T.search(/^T/)==0) IE=11;
    else IE=12; //Edge
}
else IE=13; //not IE,Edge

Put it your onload function and react accordingly (OK, so it only does IE version, Edge, or other... but ...)