# Keyboard Shortcuts

Keyboard shortcuts are a crucial part of the editor's user experience. Milkdown provides a flexible system for configuring keyboard shortcuts through presets and plugins.

## Default Shortcuts

---

Milkdown comes with a set of default keyboard shortcuts from both presets and plugins. Here's a comprehensive list of all internal shortcuts:

> #### 💡 Note
>
> `Mod` represents the platform-specific modifier key:
>
> - Windows/Linux: `Ctrl`
> - macOS: `Command`

### Commonmark Preset Shortcuts

#### Headings

| Shortcut             | Description             |
| -------------------- | ----------------------- |
| `Mod-Alt-1`          | Turn block into h1      |
| `Mod-Alt-2`          | Turn block into h2      |
| `Mod-Alt-3`          | Turn block into h3      |
| `Mod-Alt-4`          | Turn block into h4      |
| `Mod-Alt-5`          | Turn block into h5      |
| `Mod-Alt-6`          | Turn block into h6      |
| `Delete`/`Backspace` | Downgrade heading level |

#### Block Elements

| Shortcut      | Description                  |
| ------------- | ---------------------------- |
| `Mod-Shift-b` | Wrap selection in blockquote |
| `Mod-Shift-8` | Wrap in bullet list          |
| `Mod-Shift-7` | Wrap in ordered list         |
| `Mod-Shift-c` | Wrap in code block           |
| `Shift-Enter` | Insert hard break            |
| `Mod-Alt-0`   | Wrap in paragraph            |

#### Text Formatting

| Shortcut | Description        |
| -------- | ------------------ |
| `Mod-b`  | Toggle bold        |
| `Mod-i`  | Toggle italic      |
| `Mod-e`  | Toggle inline code |

### GFM Preset Shortcuts

#### Text Formatting

| Shortcut    | Description          |
| ----------- | -------------------- |
| `Mod-Alt-x` | Toggle strikethrough |

#### Tables

| Shortcut            | Description                      |
| ------------------- | -------------------------------- |
| `Mod-]`             | Move to next cell                |
| `Mod-[`             | Move to previous cell            |
| `Mod-Enter`/`Enter` | Exit table and break if possible |

## Configuring Shortcuts

---

You can customize keyboard shortcuts by configuring the keymap in the editor setup:

```typescript
import { blockquoteKeymap, commonmark } from "@milkdown/kit/preset/commonmark";

Editor.make()
  .config((ctx) => {
    ctx.set(blockquoteKeymap.key, {
      WrapInBlockquote: "Mod-Shift-b",
      // or you may want to bind multiple keys:
      WrapInBlockquote: ["Mod-Shift-b", "Mod-b"],
    });
  })
  .use(commonmark);
```

## Defining Keymaps

---

Keymaps in Milkdown are defined using the `$useKeymap` utility. Here's how to define keymaps for different features:

### Heading Keymap Example

```typescript
import { $useKeymap } from "@milkdown/utils";
import { commandsCtx } from "@milkdown/core";

export const headingKeymap = $useKeymap("headingKeymap", {
  TurnIntoH1: {
    shortcuts: "Mod-Alt-1",
    command: (ctx) => {
      const commands = ctx.get(commandsCtx);
      return () => commands.call(wrapInHeadingCommand.key, 1);
    },
  },
  TurnIntoH2: {
    shortcuts: "Mod-Alt-2",
    command: (ctx) => {
      const commands = ctx.get(commandsCtx);
      return () => commands.call(wrapInHeadingCommand.key, 2);
    },
  },
  // ... more heading levels
  DowngradeHeading: {
    shortcuts: ["Delete", "Backspace"],
    command: (ctx) => {
      const commands = ctx.get(commandsCtx);
      return () => commands.call(downgradeHeadingCommand.key);
    },
  },
});
```

### Strong (Bold) Keymap Example

```typescript
import { $useKeymap } from "@milkdown/utils";
import { commandsCtx } from "@milkdown/core";

export const strongKeymap = $useKeymap("strongKeymap", {
  ToggleBold: {
    shortcuts: ["Mod-b"],
    command: (ctx) => {
      const commands = ctx.get(commandsCtx);
      return () => commands.call(toggleStrongCommand.key);
    },
  },
});
```

### Keymap Structure

Each keymap definition follows this structure:

```typescript
$useKeymap('keymapName', {
  CommandName: {
    shortcuts: string | string[],  // Single shortcut or array of shortcuts
    priority?: number,             // (Optional) Priority of the shortcut
    command: (ctx) => () => {      // Command to execute
      const commands = ctx.get(commandsCtx);
      return () => commands.call(commandKey, ...args);
    },
  },
});
```

## Creating Custom Shortcuts

---

If you need to add custom shortcuts, you can create a keymap plugin:

```typescript
import { $useKeymap } from "@milkdown/utils";
import { commandsCtx } from "@milkdown/core";

const customKeymap = $useKeymap("customKeymap", {
  CustomCommand: {
    shortcuts: "F1",
    command: (ctx) => {
      const commands = ctx.get(commandsCtx);
      return () => commands.call(someCommand.key);
    },
  },
});

// Usage
Editor.make().use(customKeymap).use(commonmark);
```

### Example: Custom Command with Shortcut

```typescript
import { $command, $useKeymap } from "@milkdown/utils";
import { commandsCtx } from "@milkdown/core";

// Create a custom command
const customCommand = $command("CustomCommand", (ctx) => () => {
  return (state, dispatch) => {
    // Command implementation
    return true;
  };
});

// Create a keymap
const customKeymap = $useKeymap("customKeymap", {
  CustomCommand: {
    shortcuts: ["F1", "Mod-F1"], // Multiple shortcuts
    command: (ctx) => {
      const commands = ctx.get(commandsCtx);
      return () => commands.call(customCommand.key);
    },
  },
});

// Usage
Editor.make().use(customCommand).use(customKeymap);
```

## Shortcut Priority

You can control the order in which shortcuts are handled by specifying a `priority` property. Shortcuts with higher priority values are handled before those with lower values. This is useful if you want your custom shortcut to override or take precedence over other shortcuts that use the same key combination.

When multiple shortcuts are registered for the same key, they are executed in order of priority. If a shortcut command returns `false`, the next shortcut with the same key will be tried. If it returns `true`, no further commands for that key will be run. This allows you to chain or override shortcut behaviors as needed.

- The default priority is **50**.
- Normal priority values should be between **1** and **100**.
- Use higher numbers to ensure your shortcut is registered before others with the same key.

#### Example: Using Priority

```typescript
import { $useKeymap } from "@milkdown/utils";
import { commandsCtx } from "@milkdown/core";

export const customKeymap = $useKeymap("customKeymap", {
  CustomBold: {
    shortcuts: "Mod-b",
    priority: 100, // Highest in the normal range, so this runs first
    command: (ctx) => {
      const commands = ctx.get(commandsCtx);
      return () => {
        // Custom bold logic
        return true;
      };
    },
  },
  CustomAnotherBold: {
    shortcuts: "Mod-b",
    priority: 75, // Lower priority, will run only if CustomBold returns false
    command: (ctx) => {
      const commands = ctx.get(commandsCtx);
      return () => {
        // Custom italic logic
        return true;
      };
    },
  },
});
```