core(cls): shorten description

[connorjclark]

It's a bit long ...

I shortened it without removing any information - simplified the grammar constructs (being a ... is a longer way to say is).

Further ideas for simplification / changes:

A layout shift is any movement an element makes once it is visible
->
A layout shift is when an element moves.

Layout shifts are recorded, scored, and then aggregated into a cumulative score between 0 and 1; 0 is a stable page, and >=0.5 is a highly shifting page
->
Layout shifts are aggregated into a score between 0 and 1; 0 is a stable page, and >=0.5 is a highly shifting page

0.5 seems like a high range. even 0.33 looks "highly shifting"

"between 0 and 1" is not true. CLS can be >1.

[paulirish]

i think we can drop the scoring bit. the learnmore link covers that.

here's my attempt at a really terse explanation:

Cumulative Layout Shift measures the amount of layout changes of visible elements within the viewport, scaled by element size and movement distance.

[connorjclark]

Cumulative Layout Shift measures the amount of layout changes of visible elements

i raise you this

[brendankenny]

I'll cede this one to @paulirish

[paulirish]

Cumulative Layout Shift measures the amount of layout changes of visible elements

i raise you this

works for me.

[connorjclark]

wording was a little awkward and I didn't like reusing 'layout'

Cumulative Layout Shift measures how much visible elements move around the page

[brendankenny]

wording was a little awkward and I didn't like reusing 'layout'

Cumulative Layout Shift measures how much visible elements move around the page

Now i'm not so sure about this :)

"how much" causes a miscue for me while reading, where I think the thing immediately after it is what's being measured, then it reads like a grammar error ("how much visible elements?") and then I realize "move" is what is being measured, but by then I've lost the flow.

If we want to keep this general form, something like

Cumulative Layout Shift measures the movement of visible elements around the page.

(or within the viewport, etc) could also work.

[paulirish]

sure.

i like:

Cumulative Layout Shift measures the movement of visible elements within the viewport.