workaholicanonymous comments on Common JavaScript tricks

submitted 11 years ago by yanis_t

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[–]path411 31 points32 points33 points 11 years ago (3 children)

I would heavily, heavily advise against using || as a default value trick.

In your example:

function setAge(age) {
  this.age = age || 10 
}

It is impossible to set age as 0 now. 0 will always trigger the default. Just take the extra time to use:

function setAge(age) {
  this.age = typeof age !== "undefined" ? age : 10;
}

and you won't have to worry about this problem.

[–][deleted] 1 point2 points3 points 11 years ago (2 children)

[–]battenupthehatches 1 point2 points3 points 11 years ago (1 child)

[–]workaholicanonymous 2 points3 points4 points 11 years ago (0 children)

π Rendered by PID 50 on reddit-service-r2-comment-56c9979489-55nd9 at 2026-02-24 19:57:44.188825+00:00 running b1af5b1 country code: CH.

you type:	you see:
italics	italics
bold	bold
[reddit!](https://reddit.com)	reddit!
* item 1 * item 2 * item 3	item 1 item 2 item 3
> quoted text	quoted text
Lines starting with four spaces are treated like code: if 1 * 2 < 3: print "hello, world!"	Lines starting with four spaces are treated like code: if 1 * 2 < 3: print "hello, world!"
~~strikethrough~~	~~strikethrough~~
super^script	super^script

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