Unless this team perfectly did a 1:1 replacement of jQuery calls with equivalent native JS functions, this isn't "removing a 30KB dependency reduced blocking time by 11%."
It's "we rewrote our JS and it reduced blocking time"
Talking to developers sometimes feels like hitting the same wall when I talk to people about whether putting all of your money into a house is a sound investment strategy.
There's a lot of willful blindness about cost structures. If it were just one or two people you might conclude that folks are trying to sweep things under the rug, and when I was just starting out I did feel that way. But it's so consistent that I often end up bonding with people who don't feel that way, without putting Dunbar's Number into any sort of danger.
One of the hardest "Code smell" issues I've had to contend with is the habit of people to spread out problems so thin that you can no longer see them, because they're everywhere. Like being in a room with a bad smell, eventually you can't detect it without a major change of perspective. Even though everyone new who comes in starts with, "what is that smell?"
11% of your blocking time on a library could be a perfectly reasonable *budget*. The mistake is not having a goal, or assuming the goal is zero. Zero is dumb, because if that's your target then we'd be talking a static HTML page and then why are they paying you? So what's your real budget? And given that budget, what's a reasonable proportion for different concerns? 1/9th spent on a library is probably a bargain.
Stuck out to me too, but the article is wrong, they didn't "reduce blocking time" by 11%, they reduced how long it takes to complete "JS Long Tasks" by 11% (63ms).
They do claim a "reduction in JS size" on all JS apps "between 31% and 49%."
Unless this team perfectly did a 1:1 replacement of jQuery calls with equivalent native JS functions, this isn't "removing a 30KB dependency reduced blocking time by 11%."
It's "we rewrote our JS and it reduced blocking time"