Who's going to write code like that anyways? Everyone's moving to ES modules, where `this` for accessing the global is just `undefined`. It's highly unlikely that any concept other than "global object" will ever be conceived by the vast majority of users, especially future users.
On Fri, Oct 4, 2019 at 12:33 PM Boris Zbarsky <[email protected]> wrote: > > On 10/4/19 2:39 PM, #!/JoePea wrote: > >> but the global `this` you captured still has the same identity as the new > >> reference. > > > > Interesting, I never knew that. Do you have a code sample to show how > > to detect or prove that? > > Sure. The following code logs "true, 5, 5, 5, 5, true, undefined, > undefined, undefined, 5" in Firefox, Chrome, and Safari, which shows > both the identity staying the same and the property disappearing from > the WindowProxy, as well as showing the difference between the > WindowProxy and the Window (the bareword lookup finds the var on the > global, which is the Window, while `self.something` goes through the > WindowProxy, which now points to the new `Window`): > > <!DOCTYPE html> > <body> > <script> > var state = "first-load"; > var cachedThis; > var cachedValueGetter; > var cachedBarewordGetter; > function loadHappened(iframe) { > var win = iframe.contentWindow; > > if (state == "first-load") { > cachedThis = win.getGlobalThis(); > cachedValueGetter = win.getPropertyValue; > cachedBarewordGetter = win.getBareword; > console.log(win == cachedThis); > console.log(win.something); > console.log(cachedThis.something); > console.log(cachedValueGetter()); > console.log(cachedBarewordGetter()); > state = "second-load"; > iframe.srcdoc = iframe.srcdoc.replace("var something = 5;", ""); > return; > } > > console.log(frames[0] == cachedThis); > console.log(frames[0].something); > console.log(cachedThis.something); > console.log(cachedValueGetter()); > console.log(cachedBarewordGetter()); > } > </script> > <iframe srcdoc=" > <script> > var self = this; > var something = 5; > function getGlobalThis() { > return self; > } > function getPropertyValue() { > return self.something; > } > function getBareword() { > return something; > } > </script>" > onload="loadHappened(this)"></iframe> > </body> > > -Boris > _______________________________________________ > es-discuss mailing list > [email protected] > https://mail.mozilla.org/listinfo/es-discuss _______________________________________________ es-discuss mailing list [email protected] https://mail.mozilla.org/listinfo/es-discuss
