What does "variable || {}" in javascript? [duplicate]

Question

I've seen some code in the form of:

var vendorcode = vendorcode || {};

I've always thought that || was a logical operator. But this one is a real doozy.

See also What does “var FOO = FOO || {}” mean in Javascript? for why this commonly appears at the top of JS files. — apsillers
– apsillers, Commented Jun 15, 2015 at 19:35

deadboy · Accepted Answer · 2015-06-16 11:41:42Z

9

This code assigns {} to vendorcode if vendorcode is false-y. Meaning it's undefined, false, 0, null, etc.

If vendorcode is not false-y it'll keep its value.

You can read it out loud as: "vendorcode equals vendorcode OR {}"

answered Jun 15, 2015 at 19:27

deadboy

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1 Comment

I figure it had to do something with an assignment. I didn't realize || could be used with an assignment of a function.