In underscore.js source in many places I came across
if (obj.length === +obj.length)
Can someone explain, why do they use it?
In underscore.js source in many places I came across if (obj.length === +obj.length) Can
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In underscore.js source in many places I came across
if (obj.length === +obj.length)
Can someone explain, why do they use it?
It’s another way of writing
if (typeof obj.length == 'number'). Why they do it that way, it’s anyone’s guess. Probably trying to be clever at the expense of readability. Which is not too uncommon these days, unfortunately…Although it might be so that it can be compressed more by minifiers (YUI Compressor, Closure Compiler, UglifyJS, etc):
(a.length===+a.length)vs(typeof a.length=='number')Doing it their way would save 5 bytes, each instance.