Stop writing For loops. Start using underscore.
How many for loops did you write today? This week?
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Sure. That’s harmless enough. Ugly and weird, but not something to really complain about. But this is all too common:
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Which on the scale of bad code, isn’t even that bad, but you start throwing some
ifs in there and the insanity really starts.
I haven’t written a For loop in two years.
“The hell you say?”
It’s true. Cold turkey. Not a single one (ok, you caught me, I just wrote a couple above), and my code is easier to understand because of my abstinence.
How’d I do it?
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Or, even better:
That’s underscorejs in action. Clean, easy to read, short, no variables, stacks of semi-colons… just plain nice.
Here’s another example:
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Again, a typical use case for the time honored
for loop. Meh. Like an ex-smoker or a recently converted vegan, even the sight of the thing fills me with righteous indignation.
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As the underscore method name
filter suggests, this handy 3 lines of easy to parse code gives me a new array of awesome things.
Or maybe I’d like to do some work on the things and get a new array of the results?
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Those three functions are insanely useful on a daily basis, and don’t even scratch the surface of what underscore brings to the table.
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It seems a little weird at first, and I still hit the docs for methods like reduce above. Knowing they exist, and a flat refusal to use for loops is my primary weapon. The above methods are really just scratching the surface. The underscorejs library is filled with awesome utilities like this that can be combined together to create new and wonderful things.
The 30 day no-loop challenge
For the next 30 days, don’t write any for loops. If you see a nasty pile of those gnarly things, replace them with an each or a map. Do a little reducing. And let me know how it goes!
Beware. Underscore is the gateway to functional programming. What has been seen, can’t be unseen. In a good way!
note: As a more performant alternative to underscore, you might check out lodash
note: it should also be noted that modern browsers support the above methods natively.
Array.map exist, but to use them you likely need to create shims to fallback for cases when they don’t exist. For me, having the consistent underscore (lodash) API is much more convenient. YMMV
note: Yes, for loops are faster. I optimize for readability and ease of use for my team before squeezing performance out of CPUs. I don’t write games, or rich animated consumer experiences. Big projects, 10s of developers, code that already trends towards sprawling and messy.
The “clean readable code” optimization pays huge dividends, even if it comes at the cost of (very) marginal performance hits.
Now, if we are doing a big list of items in Angular, we focus on performance in terms of CPU, but even then, the only time we hit a wall with an unoptimized datagrid was on last-gen Android phones.
Clean first! ;)