Add a rule to the compiler options to disallow the `assert` keyword for import attributes

🔍 Search Terms

"import assertions", "import attributes", "assert"

✅ Viability Checklist

• This wouldn't be a breaking change in existing TypeScript/JavaScript code
• This wouldn't change the runtime behavior of existing JavaScript code
• This could be implemented without emitting different JS based on the types of the expressions
• This isn't a runtime feature (e.g. library functionality, non-ECMAScript syntax with JavaScript output, new syntax sugar for JS, etc.)
• This isn't a request to add a new utility type: https://github.com/microsoft/TypeScript/wiki/No-New-Utility-Types
• This feature would agree with the rest of our Design Goals: https://github.com/Microsoft/TypeScript/wiki/TypeScript-Design-Goals

⭐ Suggestion

Currently Stage 3 Import Attributes deprecates the assert keywords and is working to remove them from the spec if possible. V8 will remove support for the assert keywords, so Node.js and Chrome will follow suit.

Hey, quick update on this. Node.js is planning to remove support for assert in v22 (which will be released in April) and Chrome in v126 (which will be released in May).

https://github.com/denoland/deno/issues/17944#issuecomment-2027005952

I would like to remove support for the assert keywords from TypeScript as well, and would like to add disallowAssertKeywords to the compiler options as a beginning.

FYI

JSR bans publishing of TypeScript/JavaScript files that use the assert keywords.
https://github.com/jsr-io/jsr/pull/427

I've made a PR for swc, but it is pending because I can't include features that are not in tsc.
https://github.com/swc-project/swc/pull/8913

📃 Motivating Example

The following code will fail if the disallowAssertKeywords option is enabled.

import foo from "./foo.json" assert { type: "json" };

💻 Use Cases

1. What do you want to use this for?

Deno / JSR

2. What shortcomings exist with current approaches?

Deprecated the assert keywords cannot be rejected

3. What workarounds are you using in the meantime?

N/A

No files or tests are named. Start by locating the compiler option definitions and the handling and tests for import attributes; the requested behavior is to reject import ... assert { type: "json" } when disallowAssertKeywords is enabled.