Javascript check function arguments

Question

How do I check that a function has received no arguments? For example, I want to be able to create a custom function which accepts multiple inputs like so:

clear();      // clear all
clear('a');   // clear a
clear('b');   // clear b
clear('c');   // clear c
clear('d');   // clear d

VisioN · Accepted Answer · 2013-01-12 01:20:48Z

7

You may either check if an argument is undefined:

function clear(variable) {
    if (variable === undefined) { ... }
}

or simply check the number of arguments:

function clear(variable) {
    if (arguments.length === 0) { ... }
}

answered Jan 12, 2013 at 1:20

VisioN

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3 Comments

JaPerk14 Over a year ago

Is one more effective or efficient than the other?

zzzzBov Over a year ago

there's a minor bit of nuanced difference between the two. clear(undefined) will clear all in the first, but not in the second.

VisioN Over a year ago

@JaPerk14 Agree with zzzzBov here. The first will work unless you need to pass undefined as an argument. Otherwise both variants are same good. Maybe the second is slightly more foolproof.

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