Why stack trace shows 3 calls on one line inside .ts file

Question

I have the following line of code inside main.ts:

platform.bootstrapModule(AppModule);

And in call stack it's shown as 3 calls like this:

Why?

Answer 1

Yes, indeed, here is the JS code

(function (System, SystemJS) {
    (function (require, exports, module, __filename, __dirname, global, GLOBAL) {
        "use strict";
        var platform_browser_dynamic_1 = require("@angular/platform-browser-dynamic");
        var app_module_1 = require("./app.module");
        var platform = platform_browser_dynamic_1.platformBrowserDynamic();
        platform.bootstrapModule(app_module_1.AppModule);
        //# sourceMappingURL=main.js.map
    }).apply(__cjsWrapper.exports, __cjsWrapper.args);
})(System, System);

that is mapped to

platform.bootstrapModule(AppModule);

and indeed there are 3 function calls before bootstrapModule is called:

outer IIFE, inner IIFE, and platform.bootstrapModule(app_module_1.AppModule);.