# Customizing keyboard shortcuts

Keyboard shortcuts are easily customized. Provide a `keyMap` config object with the keyboard key or key combination as 
the property name, and the action (function name) as value. Key combinations are case-insensitive. 

Please note that Scheduler does not currently provide any default keyboard shortcuts on its own (it is a 
work-in-progress). But, since Scheduler is a subclass of Grid, many of Grid's keyboard shortcuts works on the Scheduler 
as well. That is why most examples below is based on Grid keyboard shortcuts.

```javascript
const scheduler = new Scheduler({
    // These shortcuts comes from Grid, but works on the Grid region of the Scheduler.
    keyMap: {
        // Changing keyboard navigation to respond to WASD keys.
        w : 'navigateUp',
        a : 'navigateLeft',
        s : 'navigateDown',
        d : 'navigateRight',
        
        // Removes mappings for arrow keys.
        ArrowUp    : null,
        ArrowLeft  : null,
        ArrowDown  : null,
        ArrowRight : null
    }
});
```

Modifier keys (`Ctrl`, `Alt`, `Shift`) are also supported. Please note that `Ctrl` is the equivalent to `Command` and
`Alt` is the equivalent to `Option` for Mac users.

```javascript
const scheduler = new Scheduler({
    // These shortcuts comes from Grid, but works on the Grid region of the Scheduler
    keyMap: {
        'Ctrl+h'       : 'navigateFirstColumn',
        'Ctrl+e'       : 'navigateLastColumn',
        'Ctrl+Shift+h' : 'navigateFirstCell',
        'Ctrl+Shift+e' : 'navigateLastCell'
    }
});
```

## Features

Scheduler features provides their own keyboard shortcuts. These will be applied to the Scheduler's keyMap with the
feature name prefixed to their action. A feature keyboard shortcut can be customized by the Scheduler's keyMap:

```javascript
const scheduler = new Scheduler({
    // Customize feature's keyMap in Scheduler's keyMap
    keyMap: {
        'Ctrl+Shift+C'   : 'eventCopyPaste.copy',
        'Ctrl+Shift+X'   : 'eventCopyPaste.cut',
        'Ctrl+C'         : null,
        'Ctrl+X'         : null
    }
});
```

## Multi-action combinations

A keyboard combination can sometimes be used for multiple actions across different components and different features.
For most of these cases only one of the action handlers will recognize the action as something it will apply its logic
to. However, some actions do collide. And for that there is a prioritization configuration property named `weight`  
built-in to the keyMap functionality.

```javascript
// Example of a configuration with a weight
const scheduler = new Scheduler({
    keyMap: {
        'Space': { handler: 'myCustomAction', weight: 100 }
    }
});
```

Please note that customizing these keyboard shortcuts can have side effects not intended and not always easily
recognizable. A quick way to get the complete list of active keyboard shortcuts is when the Scheduler has finished its
configuration process, log out the value of the property `keyMap` of the Scheduler instance object.

If you know what you are doing, the `weight` configuration can be a tool to configure more actions for the same keyboard
combination. The colliding actions will be put in an array sorted by the largest `weight` last. The actions will then be
called from beginning to end, until one not returns `false`. Not providing a `weight` puts the action on the top of the
queue.

```javascript
const scheduler = new Scheduler({
    feature: {
        tree: { // Tree feature
            keyMap : {
                // Instead of using a string action, use an object with a
                // handler and a weight property.
                ' ' : { handler: 'toggleCollapseByKey', weight: 1000}
                // This will affect the Tree feature's Space keyboard shortcut
                // to (probably) be called last of all actions on Space.
            }
        }
    }
});
```

Removing a weighted keyboard combination action is almost always safe to do:

```javascript
const scheduler = new Scheduler({
    keyMap: {
        // Changing keyboard navigation in the grid part to respond
        // to WASD keys.
        w : 'navigateUp',
        a : 'navigateLeft',
        s : 'navigateDown',
        d : 'navigateRight',
        
        // Removes mappings for arrow keys. These all have a weight, 
        // but removal is safe to do
        ArrowUp    : null,
        ArrowLeft  : null,
        ArrowDown  : null,
        ArrowRight : null
    }
});
```
## Adding new keyboard combination actions

If you want to run a function by a keyboard combination it is very easy to set up using the keyMap configuration. Either
add a new function to your Scheduler class, use an existing function from the API or just provide a function or a 
function handle in the configuration.

```javascript
const scheduler = new Scheduler({
    keyMap : {
        // This is a function from the existing Scheduler API
        'Ctrl+T'       : 'scrollToTop',

        // This is a function provided directly in the configuration object
        'Ctrl+O'       : () => location.href = './logout'
    }
});

class MyScheduler extends Scheduler {
    static configurable = {
        keyMap: {
            // This function must be available on the Scheduler subclass
            'Ctrl+Shift+M' : 'sendReminderEmail',
        }
    };
    
    sendReminderEmail(){
        myApi.post('./sendmail');
    }
}
```

If the current keyboard shortcut has multiple actions, and you want actions after your action to be called, the function
should return `false`. This will make the keyMap functionality continue calling the other actions until one not returns
`false`.

```javascript
class myScheduler extends Scheduler {
    static configurable = {
        keyMap: {
            'Space': { action: 'openSomething', weight : 0 }
        }
    }
    
    openSomething(){
        new Something(this.selectedEvents).open();
        // Return false to continue calling other Space actions
        // (probably opens the context menu)
        return false;
    }
}
```


<p class="last-modified">Last modified on 2023-10-26 8:19:20</p>