The State of JS 2021: Libraries

Libraries

Link to sectionChanges Over Time
@pwim

Each line goes from 2016 to 2020. A higher point means a technology has been used by more people, and a point further to the right means more users want to learn it; or have used it and would use it again.

Legend

Rising popularity

Falling popularity

Some lines skip years.
Technologies with only one year of data are not shown.
Velocity formula = (most recent opinion - oldest opinion) + (most recent usage) - (oldest usage)
A positive velocity means the usage and/or positive opinions have increased over time.

Link to sectionLibrary Tier List
@_charkour

This chart ranks libraries based on their retention ratio (percentage of users who would use a library again). Note that libraries used by less than 10% of survey respondents are not included.

	Front-end Frameworks
	Back-end Frameworks
	Testing
	Build Tools
	Mobile & Desktop
	Monorepo Tools

90%

97%

Vite

96%

esbuild

96%

Testing Library

94%

tsc CLI

93%

Jest

91%

Cypress

91%

Next.js

80%

89%

Svelte

88%

Storybook

87%

Express

85%

Nest

84%

npm Workspaces

84%

Rollup

84%

React

82%

Capacitor

82%

Electron

82%

Puppeteer

82%

Nuxt

80%

Yarn Workspaces

80%

Parcel

80%

Vue.js

60%

77%

React Native

76%

Strapi

75%

Expo

75%

webpack

73%

Preact

69%

Mocha

60%

Lerna

57%

Jasmine

54%

Ionic

51%

Gatsby

45%

Angular

33%

Browserify

28%

Gulp

26%

Cordova

Link to sectionRetention vs Usage
@reactathon

This chart shows each technology's retention ratio over its total user count. It can be divided into four quadrants:

1: Low usage, high retention. Technologies worth keeping an eye on.
2: High usage, high retention. Safe technologies to adopt.
3: Low usage, low retention. Technologies that are harder to recommend currently.
4: High usage, low retention. Reassess these technologies if you're currently using them.

	Front-end Frameworks
	Back-end Frameworks
	Testing
	Build Tools
	Mobile & Desktop
	Monorepo Tools

Link to sectionTechnology Usage Cardinality
@ionos_com

For each section, which percentage of respondents use (defined as having answered “would use again”) one, two, three, etc. technologies. The bottom-most bar represents the sum of all other bars.

Front-end Frameworks

∑

81.8%

37.4%

28.3%

11.4%

3.4%

1.0%

0.2%

0.1%

0.0%

Back-end Frameworks

∑

72.4%

22.7%

23.6%

14.4%

7.1%

3.1%

1.0%

0.3%

0.1%

0.0%

Testing

∑

69.9%

11.1%

12.7%

14.5%

13.7%

9.7%

5.2%

2.1%

0.7%

0.2%

0.0%

Build Tools

∑

77.9%

11.8%

21.3%

18.1%

12.7%

7.7%

4.0%

1.7%

0.5%

0.1%

0.0%

Mobile & Desktop

∑

48.4%

18.3%

14.7%

9.4%

4.0%

1.4%

0.5%

0.1%

0.0%

Monorepo Tools

∑

37.9%

21.8%

11.0%

3.7%

1.2%

0.2%

0.0%

Libraries

Link to sectionChanges Over Time@pwim

Link to sectionLibrary Tier List@_charkour

Link to sectionRetention vs Usage@reactathon

Link to sectionTechnology Usage Cardinality@ionos_com

Front-end Frameworks

Back-end Frameworks

Testing

Build Tools

Mobile & Desktop

Monorepo Tools

Link to sectionChanges Over Time
@pwim

Link to sectionLibrary Tier List
@_charkour

Link to sectionRetention vs Usage
@reactathon

Link to sectionTechnology Usage Cardinality
@ionos_com