const average = arr => arr.reduce((a, b) => a + b, 0) / arr.length;
optimised code (Benchmark)
const average = arr => arr.reduce((a, b) => a + b) / arr.length
Returns the average of the sum of all items in a numerical array.
Beware of JavaScripts Automatic Type Conversion if your Array contains something else than Numbers.
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.
Follow me on Twitter: @martinkr and consider to buy me a coffee
Photo by zoo_monkey on Unsplash
Top comments (9)
The initial value of 0 is unnecessary. The function will be faster without it (but it will error if you pass an empty array - which is arguably desirable behaviour since getting a result of
NaNwith an empty array in the original function is also nonsensical).Hi Randy,
thank you for your contribution.
I was curious about your suggestion and created a performance test on hasty.dev. When I run the tests on Chrome and Safari the original version is faster for me.
Do you mind taking a look?
Cheers,
Martin
On Chrome - the two methods are practically neck and neck. On Firefox, the second one is consistently faster, but not by a huge amount. The second should logically be faster as it performs 1 less loop than the one with the initial 0.
Performance Link
Logically yes, but it's like 10% faster - also at the url you set up - with an initial 0 for me.
On the link above (all tests on my macbook) - Chrome has near identical speed for both functions (occasionally the first will be faster than the other, but also sometimes the second). On Firefox, the second function is always faster. So, on balance it seems that without initialising the 0 is faster overall (as logically expected). The JS engine in Chrome is clearly doing some smarter optimisation
Update: Just tried Chrome and Firefox on Ubuntu too - same results as for the macbook
Hmm ... let's say ... we'll just go with the logic and I'll update the article and the code. :D
Thank you for your time and investigations.
The code editing on Hasty is really buggy too
you are missing a
>to create the phat arrow to define the first function (just afterarr)Thank you!
I adjusted the article.