Native JSR imports

Tools that natively support JSR can import JSR packages using the jsr: scheme. This allows for more efficient installation of JSR packages, and better support for JSR’s features.

Currently, the only tool that natively supports JSR is Deno. If you use a different tool, you can use JSR’s npm compatibility layer to use JSR packages.

Would you like to add native support for JSR to your tool? Check out the guide for implementing native jsr: support.

Installing and importing JSR packages

In tools with native JSR support, JSR packages do not need to be explicitly installed. Instead, you can import them using the jsr: scheme in your import specifier, and the tool will automatically download and cache the package on first run.

For example, to import the @luca/cases package:

import { camelCase } from "jsr:@luca/cases";

This will automatically download and cache the latest version of the @luca/cases package.

You can also specify version constraints in the import specifier, to import a specific version of a package:

// Import a specific patch version
import { camelCase } from "jsr:@luca/cases@1.0.0";

// Import the latest version in a major version range
import { camelCase } from "jsr:@luca/cases@1";

// Import the latest version compatible with a specific version (>= 1.2.3 and < 2.0.0)
import { camelCase } from "jsr:@luca/cases@^1.2.3";

// Import the latest version in a minor version range, greater than the specific version (>= 1.2.3 and < 1.3.0)
import { camelCase } from "jsr:@luca/cases@~1.2.3";

If you’d like to import packages without having to write the jsr: and version constraints in your code, you can use an import map to map the jsr: scheme to a different prefix.

In Deno you can do this by adding a line to the "imports" section in your deno.json. You can do this manually, or by using the deno add command:

 {
   "imports": {
+    "@luca/cases": "jsr:@luca/cases@1"
   }
 }

You can then import packages using the alias defined in the deno.json:

import { camelCase } from "@luca/cases";

Implementing native jsr: imports in tools

Note: This section is for tool maintainers who would like to add native JSR support to their tool. Are you a user of JSR instead? Go to usage instructions.

This section is still TODO. If you’d like to add native JSR support to your tool, please reach out to us - we’d love to help you get started!