When creating a chart, you want to tell the viewer what data they are viewing. To do this, you need to label the axis.
## Scale Title Configuration
The scale label configuration is nested under the scale configuration in the `scaleLabel` key. It defines options for the scale title. Note that this only applies to cartesian axes.
| Name | Type | Default | Description
| -----| ---- | --------| -----------
| `display` | `Boolean` | `false` | If true, display the axis title.
| `lineHeight` | `Number|String` | `1.2` | Height of an individual line of text (see [MDN](https://developer.mozilla.org/en-US/docs/Web/CSS/line-height))
It is also common to want to change the tick marks to include information about the data type. For example, adding a dollar sign ('$'). To do this, you need to override the `ticks.callback` method in the axis configuration.
In the following example, every label of the Y axis would be displayed with a dollar sign at the front..
If the callback returns `null` or `undefined` the associated grid line will be hidden.