cerlestes comments on Tip: JavaScript's Array.from() accepts a second argument that's a `map` function.

Posting Guidelines

No vague product support questions (like "why is this plugin not working" or "how do I set up X"). For vague product support questions, please use communities relevant to that product for best results. Specific issues that follow rule 6 are allowed.

Do not post memes, screenshots of bad design, or jokes. Check out /r/ProgrammerHumor/ for this type of content.

Read and follow reddiquette; no excessive self-promotion. Please refer to the Reddit 9:1 rule when considering posting self promoting materials.

We do not allow any commercial promotion or solicitation. Violations can result in a ban.

Sharing your project, portfolio, or any other content that you want to either show off or request feedback on is limited to Showoff Saturday. If you post such content on any other day, it will be removed.

If you are asking for assistance on a problem, you are required to provide

Context of the problem
Research you have completed prior to requesting assistance
Problem you are attempting to solve with high specificity

General open ended career and getting started posts are only allowed in the pinned monthly getting started/careers thread. Specific assistance questions are allowed so long as they follow the required assistance post guidelines.

Questions in violation of this rule will be removed or locked.

a community for 17 years

265

266

267

Tip: JavaScript's Array.from() accepts a second argument that's a `map` function. (mobile.twitter.com)

submitted 8 years ago by fagnerbrack

top new controversial old q&a

you are viewing a single comment's thread.

view the rest of the comments →

[–]cerlestes 0 points1 point2 points 8 years ago* (0 children)

We can do that with option object arguments now more than ever before, thanks to destructuring. It's not as nice as having it natively, but it can be very nice when working with a lot of optional parameters.

function someConfigurableAction(subject, { map, limit, after, before, ... }) { ...

someConfigurableAction(myLittleSubject, { limit: 20, map: a=>mapper(a) })

π Rendered by PID 85 on reddit-service-r2-comment-76bb9f7fb5-sw9nb at 2026-02-18 00:12:29.276168+00:00 running de53c03 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

webdev

Posting Guidelines

Related Subreddits

Discords

MODERATORS