README.md

TC39 proposals Short Survey

Date

The survey ran between 2025-04-07 - 2025-04-15 and was shown to all users of MDN JavaScript pages.

Questions

1. Please rank these proposals in order of preference for inclusion in JavaScript:

   Respondents were asked to drag and drop the following proposals into a ranked list. Not all proposals had to be ranked and respondents could rank as few or as many proposals as they wanted.

   Respondents were also presented with a link to a document which described the proposals.

   The proposals were presented in a random order for each respondent.

   • Decorators
   • ESM phase imports
   • Deferred module evaluation
   • JSON.parse source text access
   • Source phase imports
   • Joint iteration
   • Iterator sequence

2. Please tell us more about how your top ranking option would help you as a developer

   Free-form text

Results

The survey received 2220 responses.

Results in csv format

Interpretation

The following interpretations are proposed by Patrick Brosset, product manager at Microsoft Edge.

Final ranking of proposals

Here is the final ranking of the proposals:

Proposal	Overall rank	Score	No. of rankings
Decorators	1	8769	1736
ESM phase imports	2	7029	1675
Deferred module evaluation	3	6963	1677
JSON.parse source text access	4	6903	1646
Source phase imports	5	6852	1675
Joint iteration	6	5856	1604
Iterator sequence	7	5821	1609

The above data shows that Decorators is the most highly ranked proposal.

Here is a chart comparing the scores of the proposals:

Top ranked proposal per-respondent

The following table and chart show how many times each proposal was selected as the top ranked proposal by respondents:

Proposal	No. of top rankings	Percentage of top rankings
Decorators	757	40%
ESM phase imports	136	7.2%
Deferred module evaluation	238	12.6%
JSON.parse source text access	244	12.9%
Source phase imports	130	6.9%
Joint iteration	214	11.3%
Iterator sequence	172	9.1%

Decorators was the most popular choice, with 40% of respondents ranking it as their top choice, far ahead of the next most popular choice, JSON.parse source text access, which was ranked first by 12.6% of respondents.

Decorators

Here are the main categories that emerge from the free-form responses from people who ranked Decorators as their top choice:

Category	Number of comments
Cleaner, more ergonomic, shorter code (less repetition, better abstraction, more expressive, easier to read, more maintainable, less boilerplate)	86
Generally useful (either using it already, or would use it but have been waiting for it for years)	65
Parity with other languages and frameworks (Java, C#, PHP, Rust, Python, Dart, Nest.js, Django)	32
Parity with Typescript and/or Angular (waiting for the non-standard TS implementation to be standardized)	24
Useful for web components, custom elements, parity with Lit	15
Better performance, less dependencies, no need for a build step if implemented natively	11
Use case: Logging	11
Useful for libraries	7
Useful but not essential	6
Use case: Dependency injection	6
Use case: Memoization	6
Use case: Debugging	4
Use case: Input and data validation	4
Use case: ORM	3
Use case: Authentication, authorization, and other middlewares	2
Use case: Measure function execution time	2
Use case: Serialization	2
Use case: Function result caching	1
Use case: Testing	1
Use case: Clean-up after function execution (close files, database connections, etc.)	1

The vast majority of people who picked Decorators as their top choice did so because they find it useful for writing cleaner, more ergonomic, and shorter code. Many also mentioned that they have been waiting for the feature for a long time in JavaScript, and that they have been using it in other languages already.

ESM phase imports

Here are the main categories that emerge from the free-form responses from people who ranked ESM phase imports as their top choice:

Category	Number of comments
Developer ergonomics	8
Helping with build tools and bundles	7
Better performance	6
Standardization of inconsistent implementations	2

The main reason people picked ESM phase imports as their top choice is that they find it improves developer ergonomics, helps avoid bundler issues, and improves performance.

Deferred module evaluation

Here are the main categories that emerge from the free-form responses from people who ranked Deferred module evaluation as their top choice:

Category	Number of comments
Better performance	47
Better architecture	4
Simpler architecture and code	3
Avoid circular dependencies	1

The main reason people picked Deferred module evaluation as their top choice is that it improves performance.

JSON.parse source text access

Here are the main categories that emerge from the free-form responses from people who ranked JSON.parse source text access as their top choice:

Category	Number of comments
To transport certain data types (floats, dates, bigints) from the server to the client with simpler code nicer	30
To remove the need for complex custom code or libraries	12
To more easily debug parsing issues	6
To make libraries more robust	2
For faster and more secure JSON handling code	2

The main reason people picked JSON.parse source text access as their top choice is to unlock important data type transport from the server, and simplifying their code and making it more robust at the same time.

Source phase imports

Here are the main categories that emerge from the free-form responses from people who ranked Source phase imports as their top choice:

Category	Number of comments
To simplify the integration/import of wasm and workers, and make it easier to work with bundlers (or remove the need for them)	25
Because I depend on wasm in my work and want it to be as nice to work with as possible	17
To improve performance	2

The main reason people picked Source phase imports as their top choice is because of how it makes working with WASM easier and more ergonomic.

Joint iteration

Here are the main categories that emerge from the free-form responses from people who ranked Joint iteration as their top choice:

Category	Number of comments
Reduces the need for custom code, workarounds, or libraries, leading to cleaner code	37
Unlocks unique use cases (working with data, collections, sets, maps, arrays, streams, etc)	14
Provides parity with a known paradigm/other languages	12
Improves performance	6
Is easier for new developers	1

The main reason people picked Joint iteration as their top choice is that it greatly reduces the need for custom code or libraries for handling unique use cases that, otherwise, require more complex code.

Iterator sequence

Here are the main categories that emerge from the free-form responses from people who ranked Iterator sequence as their top choice:

Category	Number of comments
More convenient, simple, efficient, and flexible code	18
Removes the need for custom or library code	7
Provides parity with other languages	7
Better performance	6

The people who picked Iterator sequence as their top choice did so mostly for convenience reasons.

Overall learnings

The main learning is that, of the seven TC39 proposals we tested, a large portion (40%) of the respondents selected Decorators as their top choice, far ahead of the other proposals, and did so because Decorators allow to write cleaner, shorter code.

A second learning is related to the motivations that respondents mentioned for choosing proposals, which mainly fall in these three categories:

• Performance improvements.
• More ergonomic code.
• Easier time working with, or altogether removing the need for, libraries and build tools.

Today's JavaScript ecosystem is filled with countless libraries, tools, and frameworks. While these can often solve real problems and fill real gaps for developers, they can also come with the risk of increased complexity, and heavier or slower front-end codebases. These are important challenges that respondents face, and which motivated their choices.

The responses we received not only showed that Decorators is a syntax feature which developers commonly want, but they also showed that developers are eager for meaningful evolutions of the JavaScript language, to help them overcome the challenges they're facing.