This is a responsive widget that mimics the native "slot-machine" style pickers now ubiquitious on our mobile devices.

Desktop browsers will get regular old <select> elements.

Browsers that meet the following criteria will get a touch-optimized slot-machine when the <select> elements are tapped.

• Supports touch events
• Supports 3D transforms
• Supports CSS transitions

ribcage-picker is a Backbone view, best served with the other great components in the ribcage-ui collection.

Try the demo

var Picker = require('ribcage-picker')
  , picker;

picker = new Picker({
  slots: {
    quantity: {
      values: {1: .5, 2: 1, 3: 1.5, 4: 2}
    , defaultKey: 5
    }
  , unit: {
      values: {
        kilograms: 'kg'
      , pounds: 'lb'
      }
    , style: 'left'
    }
  }
});

What if we wanted the quantity slot to change in response to the selected unit? Imperial units usually have fractional quantities, while Metric units have decimal quantities.

We can use .setSlot for this.

picker.setSlot('quantity', {
  values: {
    1: '1/2'
  , 2: '1'
  , 3: '1-1/2'
  , 4: '2'
  }
, style: 'left' // You can also change the style if you'd like
                // But you can't change the defaultKey anymore
                // After all, it only makes sense to use it the first time the picker is opened
});

When setSlot is used, ribcage-picker will attempt to scroll the slot to a value with the same key. If it can't find a matching key, it will try to scroll the slot as close as possible to the physical location of the last selected row.

In this example, switching between the fractional and decimal units will be seamless, because the keys correspond to equivalent values.

Pickers emit change events. You can listen for a specific slot with change:<slot>.

// Render your view when the picker changes in value
this.listenTo(picker, 'change', this.render);

// Change one slot in response to another one changing
this.listenTo(picker, 'change:unit', function (selection) {
  // Selection is {key: <something>, value: <something>}
  switch(selection.value) {
    'lb':
      this.picker.setSlot('quantity', {values: fractionalValues});
      break;

    'kg':
      this.picker.setSlot('quantity', {values: decimalValues});
      break;
  }
});

The first version of this widget was written over four years ago by the amazing Matteo Spinelli.

Without the original project, ribcage-picker would have been significantly harder to put together.

A shoutout to @techwraith, without whom ribcage-ui and this widget wouldn't have happened.

Copyright (c) 2013 Ben Ng, http://benng.me & Matteo Spinelli, http://cubiq.org/

Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.