feat(docs): describe compatibility

docs/3.api/4.advanced/2.kit.md

@@ -183,12 +183,218 @@ Options to pass in [`c12`](https://github.com/unjs/c12#options) `loadConfig` cal
 
 [source code](https://github.com/nuxt/nuxt/blob/main/packages/kit/src/compatibility.ts)
 
-- `checkNuxtCompatibility(constraints)`
-- `assertNuxtCompatibility(constraints)`
-- `hasNuxtCompatibility(constraints)`
-- `isNuxt2()`
-- `isNuxt3()`
-- `getNuxtVersion()`
+### `checkNuxtCompatibility`
+
+Checks if constraints are met for the current Nuxt version. If not, returns an array of messages. Nuxt 2 version also checks for `bridge` support.
+
+#### Type
+
+```ts
+async function checkNuxtCompatibility(
+  constraints: NuxtCompatibility,
+  nuxt?: Nuxt
+): Promise<NuxtCompatibilityIssues>;
+
+interface NuxtCompatibility {
+  nuxt?: string;
+  bridge?: boolean;
+}
+
+interface NuxtCompatibilityIssue {
+  name: string;
+  message: string;
+}
+
+interface NuxtCompatibilityIssues extends Array<NuxtCompatibilityIssue> {
+  toString(): string;
+}
+```
+
+#### Parameters
+
+##### `constraints`
+
+**Type**: `NuxtCompatibility`
+
+**Default**: `{}`
+
+Constraints to check for. It accepts the following properties:
+
+- `nuxt` (optional)
+
+  **Type**: `string`ч
+
+  Nuxt version in semver format. Versions may be defined in Node.js way, for exmaple: `>=2.15.0 <3.0.0`.
+
+- `bridge` (optional)
+
+  **Type**: `boolean`
+
+  If set to `true`, it will check if the current Nuxt version supports `bridge`.
+
+##### `nuxt`
+
+**Type**: `Nuxt`
+
+**Default**: `useNuxt()`
+
+Nuxt instance. If not provided, it will be retrieved from the context via `useNuxt()` call.
+
+### `assertNuxtCompatibility`
+
+Asserts that constraints are met for the current Nuxt version. If not, throws an error with the list of issues as string.
+
+#### Type
+
+```ts
+async function assertNuxtCompatibility(
+  constraints: NuxtCompatibility,
+  nuxt?: Nuxt
+): Promise<true>;
+
+interface NuxtCompatibility {
+  nuxt?: string;
+  bridge?: boolean;
+}
+```
+
+#### Parameters
+
+##### `constraints`
+
+**Type**: `NuxtCompatibility`
+
+**Default**: `{}`
+
+Constraints to check for. It accepts the following properties:
+
+- `nuxt` (optional)
+
+  **Type**: `string`ч
+
+  Nuxt version in semver format. Versions may be defined in Node.js way, for exmaple: `>=2.15.0 <3.0.0`.
+
+- `bridge` (optional)
+
+  **Type**: `boolean`
+
+  If set to `true`, it will check if the current Nuxt version supports `bridge`.
+
+##### `nuxt`
+
+**Type**: `Nuxt`
+
+**Default**: `useNuxt()`
+
+Nuxt instance. If not provided, it will be retrieved from the context via `useNuxt()` call.
+
+### `hasNuxtCompatibility`
+
+Checks if constraints are met for the current Nuxt version. Return `true` if all constraints are met, otherwise returns `false`. Nuxt 2 version also checks for `bridge` support.
+
+#### Type
+
+```ts
+async function hasNuxtCompatibility(
+  constraints: NuxtCompatibility,
+  nuxt?: Nuxt
+): Promise<boolean>;
+
+interface NuxtCompatibility {
+  nuxt?: string;
+  bridge?: boolean;
+}
+```
+
+#### Parameters
+
+##### `constraints`
+
+**Type**: `NuxtCompatibility`
+
+**Default**: `{}`
+
+Constraints to check for. It accepts the following properties:
+
+- `nuxt` (optional)
+
+  **Type**: `string`ч
+
+  Nuxt version in semver format. Versions may be defined in Node.js way, for exmaple: `>=2.15.0 <3.0.0`.
+
+- `bridge` (optional)
+
+  **Type**: `boolean`
+
+  If set to `true`, it will check if the current Nuxt version supports `bridge`.
+
+##### `nuxt`
+
+**Type**: `Nuxt`
+
+**Default**: `useNuxt()`
+
+Nuxt instance. If not provided, it will be retrieved from the context via `useNuxt()` call.
+
+### `isNuxt2`
+
+Checks if the current Nuxt version is 2.x.
+
+#### Type
+
+```ts
+function isNuxt2(nuxt?: Nuxt): boolean;
+```
+
+#### Parameters
+
+##### `nuxt`
+
+**Type**: `Nuxt`
+
+**Default**: `useNuxt()`
+
+Nuxt instance. If not provided, it will be retrieved from the context via `useNuxt()` call.
+
+### `isNuxt3`
+
+Checks if the current Nuxt version is 3.x.
+
+#### Type
+
+```ts
+function isNuxt3(nuxt?: Nuxt): boolean;
+```
+
+#### Parameters
+
+##### `nuxt`
+
+**Type**: `Nuxt`
+
+**Default**: `useNuxt()`
+
+Nuxt instance. If not provided, it will be retrieved from the context via `useNuxt()` call.
+
+### `getNuxtVersion`
+
+Returns the current Nuxt version.
+
+#### Type
+
+```ts
+function getNuxtVersion(nuxt?: Nuxt): string;
+```
+
+#### Parameters
+
+##### `nuxt`
+
+**Type**: `Nuxt`
+
+**Default**: `useNuxt()`
+
+Nuxt instance. If not provided, it will be retrieved from the context via `useNuxt()` call.
 
 ## Auto-imports