javascript - What's the best way to initialize empty variables in JS? -

if know variable object later, use:

var obj; 

but doesn't matter if initialize null or undefined:

var obj = null; 

or

var obj = undefined; 

for strings use:

var str = ''; 

as later on can

str += 'some text'; 

and if use null example "nullsome text".

null, undefined, empty string or 0 falsy values check if defined. correct way initialize variables if variable used object, dom node, etc.. ?

it's initialized undefined default, use that, don't have write out:

var obj; 

if want concatenate string, use '', counters use 0... use common sense.