# bun/no-eager-dynamic-import

> Disallow `import()` that runs as soon as the module is loaded

The point of `import()` is to load a module only when it's needed. An `import()` at the top level of a file runs as soon as the file is imported, so the module is always loaded. With `await`, everything that imports the file waits for it too. Move the call into the function that needs the module, or write an `import` statement.

{/* Generated by src/codegen/lint-rule-docs.ts. Do not edit this section. */}

## Configure

Off by default. To turn it on:

```toml bunfig.toml
[lint.rules]
"bun/no-eager-dynamic-import" = "error" # or "warn"
```

{/* End of the generated section. */}

## Examples

Reported:

{/* bad */}
```js
const { marked } = await import("marked");

export function render(text) {
  return marked.parse(text);
}
```

Not reported:

{/* good */}
```js
export async function render(text) {
  const { marked } = await import("marked");
  return marked.parse(text);
}
```

{/* good */}
```js
import { marked } from "marked";

export function render(text) {
  return marked.parse(text);
}
```

A function that's called right where it's defined, a `static` field, and a `static` block also run while the file loads:

{/* bad {"count": 3} */}
```js
(async () => {
  const { marked } = await import("marked");
  console.log(marked.parse(text));
})();

class Renderer {
  static parser = import("marked");
  static {
    import("./plugins.js");
  }
}
```

The `import()` that tells Vitest which module to mock is allowed in `vi.mock()`, `vi.doMock()`, `vi.unmock()`, and `vi.doUnmock()`:

{/* good */}
```js
import { vi } from "vitest";

vi.mock(import("./database.js"), () => ({ connect: vi.fn() }));
```

## When not to use it

In an ES module, a top-level `import()` is how you choose a module at run time, as in `await import(isBun ? "./bun.js" : "./node.js")`. Disable the rule on that line.