In javascript is there really a good reason to never check for boolean true || false such as if(var){}else{}? -

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i isn't duplicate please bear me.

i check boolean true||false using if() matter of course in programming. i've programmed extensively in php, in c# asp.net, bit in java, long time ago in c++, & dabled in few others. checking boolean true||false has been pretty straightforward (as far tell). in javascript i've heard, read, , otherwise been told it's bad. instead of:

if(var){}else{}

i should instead do:

if(typeof(var) !== 'undefined' || typeof(var) !== null || var !== ''){}else{}

i've been dabbler in javascript until last 6 months when i've been getting steeped in it. after getting tired of writing & re-writing long version of boolean test shown above asked friend who's done extensive js development years. friend supported i'd read, should never test boolean true or false way i'm used to. however, after discussion have stronger belief if(var){}else{} fine in js works intuitively expect (my jsfiddle testing this)

i've looked around , found various links. following seemed more relevant:

the thing convinced me usage safe , work fine 3rd answer first question linked above given incognito. js spec clear & not evaluate boolean true||false, , again have expected (though have reminded empty array object... specific javascript, while rest of expect).

can please provide definitive reason not check boolean true or false in javascrpt, realizing know difference between boolean check , equality check??

thanks in advance!

if var undefined, null or empty string falsey. can rely on part of specification of language. totally acceptable , practiced check if undefined checking truthiness.


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