Issue #26—How does Google PageSpeed work and affect SEO rankings, the cost of JavaScript in 2019, find a cost of adding an npm package and more.

        3 July 2019

#### PerformanceNewsletter

#### Issue 26

#### Editor’s Note

A lot of our customers and performance advocates out there struggle with the same question: *How do I convince the business that performance and accessibility are essential?* 

Even with numerous studies on conversion rates proving the direct correlation between them, the stakeholders fail to see the benefits and the ethics of prioritising those areas don’t seem to be enough. 

This struggle is magnified by the lack of clarity in the tools we use for tracking. How does PageSpeed affect SEO? Is the Lighthouse score important to ranking bots? So many questions go unanswered. 

That’s why this issue **focuses on bringing clarity to what measurements do matter**, so we focus on what’s most impactful.
— Karolina

#### article

## Ensure bad performance doesn’t hurt SEO rankings

The correlation between PageSpeed scores and SEO rankings in Google has long been a mystery—nobody was able to quantify how badly poor performance can hurt marketing efforts and conversions. In his article, [Ben Schwarz](https://twitter.com/benschwarz) dissects how PageSpeed is calculated and how to avoid losing valuable ranking.

[How Google Pagespeed works: Improve Your Score and Search Engine Ranking →](https://calibreapp.com/blog/how-pagespeed-works/)

#### article

## Learn about the dominant costs of processing script

Another deep-dive by [Addy Osmani](https://twitter.com/addyosmani) explaining what specific parts of JavaScript can cause performance regressions in 2019. Our devices might be getting faster and more powerful, but we're still facing significant download and execution times.

[The cost of JavaScript in 2019 →](https://v8.dev/blog/cost-of-javascript-2019)

#### tools

## Find the cost of adding an npm package

Let’s not kid ourselves. We npm install daily, often not thinking about performance, security or engineering consequences of new packages. Bundlephobia not only analyses the bundle size but also download time and ability to be tree-shaken. For example, [check React [email protected]](https://bundlephobia.com/[email protected]).

[Bundlephobia →](https://bundlephobia.com)

#### article

## Implement a font loading strategy

[Zach Leatherman](https://twitter.com/zachleat) describes the font loading strategy he developed for [CSS Tricks](https://css-tricks.com/), one of the most well-regarded publication for front-end developers and designers. If you ever wanted to learn how to approach font loading, from preload to subsetting, this is for you.

[DEVELOPING A ROBUST FONT LOADING STRATEGY FOR CSS-TRICKS →](https://www.zachleat.com/web/css-tricks-web-fonts/)

#### article

## Don’t forget about accessibility testing

[Eric Bailey](https://twitter.com/ericwbailey) weighs on how pursuing Lighthouse scores might improve SEO rankings or not move the needle at all. An interesting look at the history of Google enforcing de-ranking through multiple performance tools but forgetting accessibility in the meantime.

[lighthouse →](https://ericwbailey.design/writing/2019-05-14-lighthouse.html)

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                                It goes a long way. ✌🏻

#### Brought to you by

                              ♠ [Calibre](https://calibreapp.com/). Make the web fast for everyone.

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