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Ben Halpern
Ben Halpern

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What are the great function/method/etc. names in popular libs/languages?

Naming things is hard, but what are the ones that have stood out to you as great choices that have stood the test of time?

Top comments (31)

itsasine profile image
ItsASine (Kayla)

Testing frameworks are fun for this because by nature of what the code does, it ends up being a source of truth for how the app behaves. Thus, the test specs can kind of read like documentation.

Assuming var thing = 10;

Some Jasmine:





expect(new Promise(thing)).toEqual(10);

Some Mocha with Chai:'number');



expect(new Promise(thing)).to.eventually.equal(10);

I also just like the punny names of testing languages, to be honest.

ben profile image
Ben Halpern

Yeah, I find this especially true in Ruby, where whitespace rules can make things almost plain english (though some take this way to far. It's a balance)

tyrw profile image
Tyler Warnock

I always chuckle at React's componentDidMount vs Vue's mounted

burdettelamar profile image
Burdette Lamar

I love Ruby's naming conventions foo? and foo!.

The former is for a method that returns a boolean (like IsFoo in some languages):

irb(main):006:0> s = 'abc'
=> "abc"
irb(main):007:0> s.empty?
=> false

The latter for a method that may do something possibly unexpected, such as modifying a given argument:

irb(main):001:0> s = 'abc'
=> "abc"
irb(main):002:0> s.reverse
=> "cba"
irb(main):003:0> s
=> "abc"
irb(main):004:0> s.reverse!
=> "cba"
irb(main):005:0> s
=> "cba"
hoelzro profile image
Rob Hoelz

Perl's Carp module has some interesting naming choices:

# warn user (from perspective of caller)
carp "string trimmed to 80 chars";

# die of errors (from perspective of caller)
croak "We're outta here!";

# die of errors with stack backtrace
confess "not implemented";

Not to mention that Perl introduces lexical variables with the my keyword, and package variables with the our keyword!

jakebman profile image
jakebman • Edited

And those were named to fit the model of die (exit, failing, with message)

Also Perl's or operator is intentionally lower precedence than almost anything else so you can:

my $file = open '/dev/zero' or die "Couldn't open file";


shalvah profile image

confess 😂😂

kungtotte profile image
Thomas Landin

It's not that the name itself is great, but Python's len() keeps reminding me how well thought-out the early Python language was.

One global function with a short but intuitive name that consistently does exactly what you expect it to no matter what data structure you throw at it.

aodev profile image

The start of my journey as a programmer is a peculiar one in that regard.

As a non-native English speaker, when I started to code, a long time ago, I simply didn't understand anything. In fact, I thought that most reserved word of any language were just that: some "random strings" with no meaning outside of the programming language. It's later, when I had learned English that I got some Ah ah! moment.

Obviously for an English speaker: "if, case, switch, while, random" are just normal words. It wasn't for me. (I started to play around with code when I was a child, under MS-DOS 6)

So, talking about some great choices, my biggest and relatively recent "Ah ah! moment" has been with


I could never remember which one would round up and which one would round down.
Until a day like any other day, my brain said: "hey, wait a minute: isn't "floor", because the floor is low and "ceil(ing)" is up?" Awesome. XD

hugo__df profile image
Hugo Di Francesco

unless in Ruby, although it's more of an operator.

Everything in JavaScript (not a fanboy of course), I can't think of a specific method that's named right but I also can't think of any that are named wrong 🤔.

ben profile image
Ben Halpern

Operators are allowed—and anything related to the idea of naming things.

I too really like unless, though I see it get overused sometimes where ! would be clearer.

ericcurtin profile image
Eric Curtin • Edited

"if (!" is clearer to most devs as it is available in more languages than "unless".

manzanit0 profile image
Javier Garcia

.NET's FirstOrDefault() method when accessing LINQ. I find it super clear :)

twigman08 profile image
Chad Smith

Now only if I could convince people to quit thinking FirstOrDefault will always return null if it can't find anything.

It does what it says it does, default value. It just so happens that for objects that is null
(I say this because I had to prove to someone once that their if statement would always evaluate to true. Lol)

ben profile image
Ben Halpern

Less clear along those lines is the ||= operator.

robencom profile image

Hey, PHP has the coolest operator: the SPACESHIP operator <=>

Thread Thread
kip13 profile image

The <=> is for evaluation and ||= is for assigment, the ?? null coalescing operator is more close to it but are not the same.

nimmo profile image

Maybe in Elm, not only because it's descriptive (Maybe it has a value, and Maybe it doesn't), but when it doesn't have a value, instead of null or undefined or whatever, it's Nothing.

Which makes me think of Nathan Explosion whenever I use it.

kip13 profile image

A common problem in PHP (maybe in some other langs too) is the way to move between dates and get the incorrect value, for example when you decrease or increase a month(s):

>>> (new \DateTime('2017-01-31'))->add(new \DateInterval('P1M'))->format('Y-m-d')
=> "2017-03-03"

Carbon a good library offers some methods to avoid this behaivor and their names are really good:

>>> (new Carbon('2017-01-31'))->addMonthNoOverflow()->format('Y-m-d')
=> "2017-02-28"

If you wanna get the calculation with this behaivor, no problem:

>>> (new Carbon('2017-01-31'))->addMonthWithOverflow()->format('Y-m-d')
=> "2017-03-03"

Other methods are: createMidnightDate, localeHasDiffOneDayWords, createSafe...

galdin profile image
Galdin Raphael

Android's UserManager class has something called isUserAGoat().

Here's an interesting discussion on it 😁

phortx profile image
Benjamin Klein • Edited

I really like the convention to name mixins with-something in react and Vue. Often this feels very elegant. Like with-captcha.js or with-user.js. There couldn't be any naming that feels any smoother 😍

katafrakt profile image
Paweł Świątkowski

Not sure if this counts, but PHP's T_PAAMAYIM_NEKUDOTAYIM parser token is pretty rad yet savage :D

alshakero profile image
Omar Alshaker

I really like PHP's explode and implode couple. It's String.split and String.join for those who don't know.

rapidnerd profile image
George Marr

From one of my most recent projects

void iDontKnowIfThisIsGoingToWorkSoImPuttingOffUsingThisMethodBecauseImScaredOfTheOutcome()