one-way-select.md

{{one-way-select}}

Basics

The basic invocation of the component looks like:

{{one-way-select selectedValue
    options=options
    update=(action (mut selectedValue))
}}

This will render a <select> element with options taken from the options parameter and if the options contain selectedValue, then that option will be marked as selected.

The options parameter can either be an array or a string of words separated by spaces.

The action passed to the update parameter will be called whenever the user selects an option.

The examples here pass the value attribute as a positional parameter, but you can also pass value as an ordinary parameter:

{{one-way-select
    value=selectedValue
    options=options
    update=(action (mut selectedValue))
}}

Select element attributes

The one-way-select component supports binding all attributes a <select> element can have.

An example:

{{one-way-select selectedValue
    disabled=isDisabled
    tabindex=3
    required=true
    options=options
    update=(action (mut selectedValue))
}}

Adding a blank or prompt option

You can set the includeBlank parameter to true if you want a blank option as the first option:

{{one-way-select selectedValue
    options=options
    includeBlank=true
    update=(action (mut selectedValue))
}}

If you want to have the first option to have a placeholder text you can pass a string to the prompt parameter instead:

{{one-way-select selectedValue
    options=options
    prompt="Please select one:"
    update=(action (mut selectedValue))
}}

Set the promptIsSelectable to true if you want the user to be able to select the blank/prompt option.

Working with objects instead of strings

Let's say you have an array filled with instances of the following user model:

Model.extend({
  username: attr('string'),
  email: attr('string')
});

If you want to render a select with all the users with the option's labels being the username of the user, then you can set the optionValuePath and the optionLabelPath parameters with the apropriate values:

{{one-way-select selectedUser
    options=users
    optionValuePath="id"
    optionLabelPath="username"
    update=(action (mut selectedUser))
}}

When an option is selected then update will receive the full object as parameter, not just the value specified by optionValuePath.

If you do want to use a specific attribute of the object, then there is optionTargetPath, this behaves similarly to optionValuePath except that the selected value is equals to one of values of the property behind optionTargetPath.

data = [
  { id: 'EN', label: 'English' },
  { id: 'ES', label: 'Spanish' },
  { id: 'DE', label: 'German' }
];

{{one-way-select selectedLanguage
    options=users
    optionTargetPath="id"
    optionLabelPath="label"
    update=(action (mut selectedLanguage))
}}

In this case, when a user selects a different language, the value of selectedLanguage gets updated to the id of the object (e.g. EN).

Block expression / optionComponent

Sometimes you may want to use handlebars helpers to express the label. In this case you may use one-way-select as a block expression. The first block parameter is an option object/value. The second parameter is option index. If option groups are used, the index will be scoped to the group and the third parameter will be the group index.

const countries = ['france', 'germany', 'spain'];

{{#one-way-select selectedCountry
    options=countries
    update=(action (mut selectedCountry)) as |option index|}}
  {{index}} - {{loc option}}
{{/one-way-select}}

It is, of course, possible to use the block expression with objects.

Model.extend({
  username: attr('string'),
  role: attr('string')
});

{{#one-way-select selectedUser
    options=users
    optionValuePath="id"
    update=(action (mut selectedUser)) as |user|}}
  {{get user "username"}} ({{loc (get user "role")}})
{{/one-way-select}}

In even more extreme cases, where you feel you need to reuse the contents of the block expression, you can pass a component to optionComponent instead. The component is rendered for each option and it will pass the same parameters as are yielded to the block (option, index, groupIndex) to the component.

{{one-way-select selectedCountry
    options=countries
    optionComponent="country-option"}}

From Ember.js 2.3 and up you can also pass a component using the component helper:

{{one-way-select selectedCountry
    options=countries
    optionComponent=(component "country-option")}}

Multiple select

Changing the one-way-select into a multiple select is as easy as setting the multiple parameter to true. Please note that value should now be an array of selected items, instead of just a single item.

{{one-way-select selectedUsers
    options=users
    multiple=true
    optionValuePath="id"
    optionLabelPath="username"
    update=(action (mut selectedUsers))
}}

Grouping options

Setting the groupLabelPath parameter will cause all options which have the same value on the given path to be grouped in an <optgroup> element. The label of the <optgroup> element will be the value of the given path.

{{one-way-select selectedCity
    options=cities
    optionValuePath="id"
    optionLabelPath="name"
    groupLabelPath="state"
    update=(action (mut selectedCity))
}}

Optionally you can pass the options pre-grouped, the options then need to adhere to the following structure:

[
  {
    groupName: 'Trappist',
    options: [
      { id: 1, label: 'Dubbel', type: 'Trappist' },
      { id: 2, label: 'Tripel', type: 'Trappist' }
    ]
  },
  {
    groupName: 'IPA',
    options: [
      { id: 3, label: 'IPA', type: 'IPA' }
    ]
  }
]