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

basham

CSS units

Recommendations of unit types per media type:

Media	Recommended	Occasional use	Infrequent use	Not recommended
Screen	em, rem, %	px	ch, ex, vw, vh, vmin, vmax	cm, mm, in, pt, pc
Print	em, rem, %	cm, mm, in, pt, pc	ch, ex	px, vw, vh, vmin, vmax

Relative units

Relative units

staltz

The introduction to Reactive Programming you've been missing

(by @andrestaltz)

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This tutorial as a series of videos

If you prefer to watch video tutorials with live-coding, then check out this series I recorded with the same contents as in this article: Egghead.io - Introduction to Reactive Programming.

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phamann

Lesson's learnt building the Guardian

Below is a collection of my favourite responses I gathered from Guardian engineers when asked the question: What have you learnt starting from scratch and building a mobile-first next generation web platform for the Guardian?

Daithi O Crualaoich

• Work with great people.
• Deploy like crazy. This means the team has to control the infrastructure as well as code.
• Design is not a service. Designers have to sit in the team.
• Infrastructure is intrinsically unreliable. Discard and replace is the robust strategy.
• Use your CDN for HTML too.
• Don't always do as you are told.