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autocomplete.md

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The autocomplete is a normal text input enhanced by a panel of suggested options. You can read more about autocompletes in the Material Design spec.

Simple autocomplete

Start by adding a regular mdInput to the page. Let's assume you're using the formControl directive from the @angular/forms module to track the value of the input.

my-comp.html

<md-form-field>
   <input type="text" mdInput [formControl]="myControl">
</md-form-field>

Next, create the autocomplete panel and the options displayed inside it. Each option should be defined by an md-option tag. Set each option's value property to whatever you'd like the value of the text input to be upon that option's selection.

my-comp.html

<md-autocomplete>
   <md-option *ngFor="let option of options" [value]="option">
      {{ option }}
   </md-option>
</md-autocomplete>

Now we'll need to link the text input to its panel. We can do this by exporting the autocomplete panel instance into a local template variable (here we called it "auto"), and binding that variable to the input's mdAutocomplete property.

my-comp.html

<md-form-field>
   <input type="text" mdInput [formControl]="myControl" [mdAutocomplete]="auto">
</md-form-field>

<md-autocomplete #auto="mdAutocomplete">
   <md-option *ngFor="let option of options" [value]="option">
      {{ option }}
   </md-option>
</md-autocomplete>

Adding a custom filter

At this point, the autocomplete panel should be toggleable on focus and options should be selectable. But if we want our options to filter when we type, we need to add a custom filter.

You can filter the options in any way you like based on the text input*. Here we will perform a simple string test on the option value to see if it matches the input value, starting from the option's first letter. We already have access to the built-in valueChanges observable on the FormControl, so we can simply map the text input's values to the suggested options by passing them through this filter. The resulting observable (filteredOptions) can be added to the template in place of the options property using the async pipe.

Below we are also priming our value change stream with null so that the options are filtered by that value on init (before there are any value changes).

*For optimal accessibility, you may want to consider adding text guidance on the page to explain filter criteria. This is especially helpful for screenreader users if you're using a non-standard filter that doesn't limit matches to the beginning of the string.

Setting separate control and display values

If you want the option's control value (what is saved in the form) to be different than the option's display value (what is displayed in the actual text field), you'll need to set the displayWith property on your autocomplete element. A common use case for this might be if you want to save your data as an object, but display just one of the option's string properties.

To make this work, create a function on your component class that maps the control value to the desired display value. Then bind it to the autocomplete's displayWith property.

Keyboard interaction

  • DOWN_ARROW: Next option becomes active.
  • UP_ARROW: Previous option becomes active.
  • ENTER: Select currently active item.

Option groups

md-option can be collected into groups using the md-optgroup element:

<md-autocomplete #auto="mdAutocomplete">
  <md-optgroup *ngFor="let group of filteredGroups | async" [label]="group.name">
    <md-option *ngFor="let option of group.options" [value]="option">
      {{ option.name }}
    </md-option>
  </md-optgroup>
</md-autocomplete>