const shallowClone = arr => arr.slice(0);
Creates a shallow-copied clone of the provided array. Since it's a shallow copy, nested objects or arrays will be copied by reference, not duplicated.
The repository & npm package
You can find the all the utility functions from this series at github.com/martinkr/onelinecode
The library is also published to npm as @onelinecode for your convenience.
The code and the npm package will be updated every time I publish a new article.
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Top comments (6)
Thank you for sharing! Yes, there are multiple other ways to shallow clone an array in javascript. As so often in programming, at one point you have to choose ;)
I run benchmarks before posting and
.slice(0)was the fastest on my machine. The perf.link you posted comes up with76,280 ops/s for .slice(0)and70,030 ops/s for spread- but I think the difference is negligible. Depending on the engine and the environment it can easily be the other way around.Cheers!
I am enjoying this series too, particular attention to detail in the comments and bencharks.
I do always question the importance and benchmarks because a blink of an eye is similar to a slower blink of an eye but we are where we are in the world of JavaScript, what's always amazing is that the older ways are generally faster across the board, but I would still put convenience of writing over customer experience if the experience was marginally affected, that's just me, call me the bad guy 🤪
From my perspective, the benchamrkings are super interesting because you would expect the "new", modern functions being performance optimised (otherwise, why would you implement them?) but often, as you said, they are not. At least not yet.
Not yet indeed, I remember the
window.Proxywas introduced in Chrome for example, lots of people said, don't use it, its slow and hard for the engine to optimize, if not impossible. but then 6 months later I stumbled upon a blog by the lady who did the optimization in V8 and get it running quite a lot faster. Sadly I can't remember by how much but, it's always stuck in my mind, I'm okay with Proxy these daysI read: shadow clone (jutsu). My bad.
Keep up the series!