# Modules and import maps

Deno-first code uses standard ESM, and local imports include their real extension:

```ts
import { add } from "./math.ts";
import { join } from "jsr:@std/path";
import React from "npm:react";
```

Do not scatter versions through every source file. Use `deno add` to write project aliases to `deno.json`:

```bash
deno add jsr:@std/path npm:react
```

```json
{
  "imports": {
    "@std/path": "jsr:@std/path@^1.1.2",
    "react": "npm:react@^19.2.0",
    "@/": "./src/"
  }
}
```

Then import stable names:

```ts
import { join } from "@std/path";
import { loadConfig } from "@/config.ts";
```

## Selection order

1. Web standards or built-in Deno APIs;
2. TypeScript-first JSR packages, especially `@std/*`;
3. npm packages through `npm:` or `deno add`;
4. direct HTTPS imports only when necessary, with a trusted pinned source.

A computed dynamic import is outside the static module graph: a local path needs `--allow-read`, while a remote URL needs `--allow-import`. Static imports behave differently.

Official references: [Modules](https://docs.deno.com/runtime/fundamentals/modules/) and [Import maps example](https://docs.deno.com/examples/import_maps_tutorial/).