A Lightning Multi-Select Picklist.

To use, simply add as part of a form (or without if you'd like):

<c:MultiSelect aura:id="my-multi-select" options="{!v.options}" selectChange="{!c.handleSelectChangeEvent}" selectedItems="{!v.mySelectedItems}" />

The multiselect options are an array of objects eg {label:'label',value:'value'} and selectedItems is a comma delimited string (String[]).

The handleSelectChangeEvent method could look like this:

//changes filter parameters
handleSelectChangeEvent: function(component, event, helper) {
    var items = component.get("v.items");
    items = event.getParam("values");
    component.set("v.items", items);
}

What it looks like:

This example shows feeding in some values that will show up immediately after the component is initialized. NOTE - the type is Object[] rather than a typed SelectItem[] array. For some reason, the typed version is not parsed and is fed to the child component as a string.

Also note, I've added an init handler to the component.

<aura:application access="global" extends="force:slds" >
    
    <aura:attribute name="options" type="Object[]" default="[
  {
    'label': 'Annual Review',
    'value': 'Annual Review'
  },
  {
    'label': 'Watching Rates',
    'value': 'Watching Rates'
  },
  {
    'label': 'Initial Contact',
    'value': 'Initial Contact'
  },
  {
    'label': 'Application',
    'value': 'Application'
  },
  {
    'label': 'Waiting for Qualifying Documentation',
    'value': 'Waiting for Qualifying Documentation'
  },
  {
    'label': 'Qualifying Documentation Review',
    'value': 'Qualifying Documentation Review'
   }]"/>
    
   <c:MultiSelect options="{!v.options}" label="Testing Testing" />

</aura:application>

Init handler:

<aura:handler name="init" value="{!this}" action="{!c.init}"/>

• Changed structure to make a slds form item. If you don't want that, just remove this div.
• Added a label attribute.
• Added a variant attribute. Set to 'label-hidden' to hide the label.
• Options are now just regular javascript objects.
• Updated this file with new usage structure.
• Loading now runs once on init. A flag prevents this method being called again on options change unless reset.
• Call reInit() to load again.

You can also use a change handler to handle any changes to your options list after the component is rendered:

<aura:handler name="change" value="{!options}" action="{!c.init}"/>

Note, you may need to deal with recursion issues here - make sure your init routine doesn't change the options arrray... as it happens, most of this risk is mitigated as internally, a different list (options_) is used.

Finally, if you don't want to use a change handler, you can call this method: reInit(). It's a public method on the component that reruns the init method again.

From outside, you'd typically change the options array, find the multiselect component and call reInit()

Let me know if you find any bugs.