david-mark

Having had some of the first words on "modern" host object detection and testing, feel like it's time to try to issue a final word. At least I hope it is the last word as I've seen a lot misinformation spread over the last several years. The Web is great for that. :)

The original observations and concepts came about from discussions on comp.lang.javascript (CLJ) and were written up by Peter Michaux almost a decade ago.

The first rule to remember is that - with regard to detection - we don't know anything about host objects. How are they implemented? Why do they behave like they do? We can never really know as - unlike objects native and built into javascript (JS) implementations - there are no ECMA specifications for host objects. They are described in t

yelouafi

// We model the call stack using a linked list of Generators
// Each Generator has a _return field pointing back to its parent

function stepGen(gen, arg) {
    const {done, value} = gen.next(arg)
    if(done) {        
        if(gen._return) {
            stepGen(gen._return, value)
        }

david-mark

'use strict' Considered Pointless and Harmful

What is strict mode?

According to the MDN reference, it is:

ECMAScript 5's strict mode is a way to opt in to a restricted variant of JavaScript [sic].

It goes on to say:

chitchcock

Stevey's Google Platforms Rant

I was at Amazon for about six and a half years, and now I've been at Google for that long. One thing that struck me immediately about the two companies -- an impression that has been reinforced almost daily -- is that Amazon does everything wrong, and Google does everything right. Sure, it's a sweeping generalization, but a surprisingly accurate one. It's pretty crazy. There are probably a hundred or even two hundred different ways you can compare the two companies, and Google is superior in all but three of them, if I recall correctly. I actually did a spreadsheet at one point but Legal wouldn't let me show it to anyone, even though recruiting loved it.

I mean, just to give you a very brief taste: Amazon's recruiting process is fundamentally flawed by having teams hire for themselves, so their hiring bar is incredibly inconsistent across teams, despite various efforts they've made to level it out. And their operations are a mess; they don't real

paulirish

What forces layout / reflow

All of the below properties or methods, when requested/called in JavaScript, will trigger the browser to synchronously calculate the style and layout*. This is also called reflow or layout thrashing, and is common performance bottleneck.

Generally, all APIs that synchronously provide layout metrics will trigger forced reflow / layout. Read on for additional cases and details.

Element APIs

Getting box metrics

• elem.offsetLeft, elem.offsetTop, elem.offsetWidth, elem.offsetHeight, elem.offsetParent