Jamo Sandbox
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Date & Time Libraries

is-extendable

Returns true if a value is a plain object, array or function.

4.3Updated 2026-11-041 min read

At a glance

Weekly Downloads
72,157,683
Dependent Packages
739
License
MIT
First Published
2015

What the data shows

There's no cost to use is-extendable at all — it's free, full stop.

is-extendable is well regarded, if not quite top-tier, scoring 4.3 out of 5 on our rating metric.

Over the period tracked, is-extendable has seen a declining user base, down roughly 8% over the past 2 years.

none of the 3 tracked metrics put is-extendable above the date & time libraries average.

is-extendable dates back to 2015, making it one of the more established names in date & time libraries.

Adoption trend

2389.8M20242026

is-extendable vs. Date & Time Libraries average

Featureis-extendableDate & Time Libraries average
Weekly Downloads72,157,683126,496,512
Dependent Packages7396,160
Popularity score4.3 / 54.4 / 5

Strengths & watch-outs

Strengths

  • Free to use, with no paid tier required to get started.

Watch-outs

  • Falls short on weekly downloads — 72,157,683 against a category average of 126,496,512.
  • Falls short on dependent packages — 739 against a category average of 6,160.
  • Popularity score trails the category average: 4.3 / 5 vs. 4.4 / 5.
  • User base has been shrinking over the tracked period.

Quick answers

Is is-extendable free to use?

Yes — is-extendable is free, with no paid tier required to get started.

Is is-extendable good? What's its rating?

is-extendable scores 4.3 out of 5 on our rating metric, versus a Date & Time Libraries category average of 4.4.

How many people use is-extendable?

is-extendable has roughly 72.2M users/stars tracked, compared to a category average of 126.5M.

When was is-extendable founded?

is-extendable was founded in 2015, making it 11 years old.

Is is-extendable growing?

No — usage is down roughly 8% over the past 2 years.

Ready to see is-extendable for yourself?

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