Checkbox Input

import {
  WuiFormCheckboxGroup,
  WuiFormCheckbox,
} from "@wui/wui-vue/lib/form-checkbox";

Description

For cross browser consistency, <wui-form-checkbox-group> and <wui-form-checkbox> use WUI's custom checkbox input to replace the browser default checkbox input. It is built on top of semantic and accessible markup, so it is a solid replacement for the default checkbox input.

Example 1: Single checkbox

<template>
  <div>
    <wui-form-checkbox
      id="checkbox-1"
      v-model="status"
      name="checkbox-1"
      value="accepted"
      unchecked-value="not_accepted"
    >
      I accept the terms and use
    </wui-form-checkbox>

    <div>State: <strong>{ status }</strong></div>
  </div>
</template>

<script>
  export default {
    data() {
      return {
        status: "not_accepted",
      };
    },
  };
</script>

<!-- wui-form-checkbox.vue -->

Example 2: Multiple choice checkboxes

<template>
  <div>
    <wui-form-group label="Using options array:" v-slot="{ ariaDescribedby }">
      <wui-form-checkbox-group
        id="checkbox-group-1"
        v-model="selected"
        :options="options"
        :aria-describedby="ariaDescribedby"
        name="flavour-1"
      ></wui-form-checkbox-group>
    </wui-form-group>

    <wui-form-group label="Using sub-components:" v-slot="{ ariaDescribedby }">
      <wui-form-checkbox-group
        id="checkbox-group-10"
        v-model="selected"
        :aria-describedby="ariaDescribedby"
        name="flavour-2"
      >
        <wui-form-checkbox value="orange">Orange</wui-form-checkbox>
        <wui-form-checkbox value="apple">Apple</wui-form-checkbox>
        <wui-form-checkbox value="pineapple">Pineapple</wui-form-checkbox>
        <wui-form-checkbox value="grape">Grape</wui-form-checkbox>
      </wui-form-checkbox-group>
    </wui-form-group>

    <div>Selected: <strong>{ selected }</strong></div>
  </div>
</template>

<script>
  export default {
    data() {
      return {
        selected: [], // Must be an array reference!
        options: [
          { text: "Orange", value: "orange" },
          { text: "Apple", value: "apple" },
          { text: "Pineapple", value: "pineapple" },
          { text: "Grape", value: "grape" },
        ],
      };
    },
  };
</script>

<!-- wui-form-checkbox-multiple.vue -->

Feel free to mix and match options prop and <wui-form-checkbox> in <wui-form-checkbox-group>. Manually placed <wui-form-checkbox> inputs will appear below any checkbox inputs generated by the options prop. To have them appear above the inputs generated by options, place them in the named slot first.

Checkbox group options array

options can be an array of strings or objects. Available fields:

• value The selected value which will be set on v-model
• disabled Disables item for selection
• text Display text, or html Display basic inline html

value can be a string, number, or simple object. Avoid using complex types in values.

If both html and text are provided, html will take precedence. Only basic/native HTML is supported in the html field (components will not work). Note that not all browsers will render inline html (i.e. <i>, <strong>, etc.) inside <option> elements of a <select>.

const options = [
  "A",
  "B",
  "C",
  { text: "D", value: { d: 1 }, disabled: true },
  "E",
  "F",
];

If an array entry is a string, it will be used for both the generated value and text fields.

You can mix using strings and objects in the array.

Internally, WuiVue will convert the above array to the following array (the array of objects) format:

const options = [
  { text: "A", value: "A", disabled: false },
  { text: "B", value: "B", disabled: false },
  { text: "C", value: "C", disabled: false },
  { text: "D", value: { d: 1 }, disabled: true },
  { text: "E", value: "E", disabled: false },
  { text: "F", value: "F", disabled: false },
];

Options as an array of objects

const options = [
  { text: "Item 1", value: "first" },
  { text: "Item 2", value: "second" },
  { html: "<b>Item</b> 3", value: "third", disabled: true },
  { text: "Item 4" },
  { text: "Item 5", value: { foo: "bar", baz: true } },
];

If value is missing, then text will be used as both the value and text fields. If you use the html property, you must supply a value property.

Internally, WuiVue will convert the above array to the following array (the array of objects) format:

const options = [
  { text: "Item 1", value: "first", disabled: false },
  { text: "Item 2", value: "second", disabled: false },
  { html: "<b>Item</b> 3", value: "third", disabled: true },
  { text: "Item 4", value: "Item 4", disabled: false },
  { text: "Item 5", value: "E", disabled: false },
];

Changing the option field names

If you want to customize the field property names (for example using name field for display text) you can easily change them by setting the text-field, html-field, value-field, and disabled-field props to a string that contains the property name you would like to use:

<template>
  <div>
    <wui-form-checkbox-group
      v-model="selected"
      :options="options"
      class="mb-3"
      value-field="item"
      text-field="name"
      disabled-field="notEnabled"
    ></wui-form-checkbox-group>
    <div class="mt-3">Selected: <strong>{ selected }</strong></div>
  </div>
</template>

<script>
  export default {
    data() {
      return {
        selected: [],
        options: [
          { item: "A", name: "Option A" },
          { item: "B", name: "Option B" },
          { item: "D", name: "Option C", notEnabled: true },
          { item: { d: 1 }, name: "Option D" },
        ],
      };
    },
  };
</script>

<!-- wui-form-checkbox-group-options-fields.vue -->

Inline and stacked checkboxes

<wui-form-checkbox-group> components render inline checkboxes by default, while <wui-form-checkbox> renders block-level (stacked) checkboxes.

Set the prop stacked on <wui-form-checkbox-group> to place each form control one over the other, or if using individual checkboxes not inside a <wui-form-checkbox-group>, set the inline prop on <wui-form-checkbox>.

<template>
  <div>
    <wui-form-group
      label="Form-checkbox-group inline checkboxes (default)"
      v-slot="{ ariaDescribedby }"
    >
      <wui-form-checkbox-group
        v-model="selected"
        :options="options"
        :aria-describedby="ariaDescribedby"
        name="flavour-1a"
      ></wui-form-checkbox-group>
    </wui-form-group>

    <wui-form-group
      label="Form-checkbox-group stacked checkboxes"
      v-slot="{ ariaDescribedby }"
    >
      <wui-form-checkbox-group
        v-model="selected"
        :options="options"
        :aria-describedby="ariaDescribedby"
        name="flavour-2a"
        stacked
      ></wui-form-checkbox-group>
    </wui-form-group>

    <wui-form-group
      label="Individual stacked checkboxes (default)"
      v-slot="{ ariaDescribedby }"
    >
      <wui-form-checkbox
        v-for="option in options"
        v-model="selected"
        :key="option.value"
        :value="option.value"
        :aria-describedby="ariaDescribedby"
        name="flavour-3a"
      >
        { option.text }
      </wui-form-checkbox>
    </wui-form-group>

    <wui-form-group
      label="Individual inline checkboxes"
      v-slot="{ ariaDescribedby }"
    >
      <wui-form-checkbox
        v-for="option in options"
        v-model="selected"
        :key="option.value"
        :value="option.value"
        :aria-describedby="ariaDescribedby"
        name="flavour-4a"
        inline
      >
        { option.text }
      </wui-form-checkbox>
    </wui-form-group>
  </div>
</template>

<script>
  export default {
    data() {
      return {
        selected: [], // Must be an array reference!
        options: [
          { text: "Orange", value: "orange" },
          { text: "Apple", value: "apple" },
          { text: "Pineapple", value: "pineapple" },
          { text: "Grape", value: "grape" },
        ],
      };
    },
  };
</script>

<!-- wui-form-checkbox-stacked.vue -->

Checkbox values and v-model

By default, <wui-form-checkbox> value will be true when checked and false when unchecked. You can customize the checked and unchecked values by specifying the value and unchecked-value properties, respectively.

The v-model binds to the checked prop. When you have multiple checkboxes that bind to a single data state variable, you must provide an array reference ([]) to your v-model. Do not use the checked prop directly.

Note that when v-model is bound to multiple checkboxes (i.e an array ref), the unchecked-value is not used. Only the value(s) of the checked checkboxes will be returned in the v-model bound array. You should provide a unique value for each checkbox's value prop (the default of true will not work when bound to an array)

To pre-check any radios, set the v-model to the value(s) of the checks that you would like pre-selected.

When placing individual <wui-form-checkbox> components within a <wui-form-checkbox-group>, most props and the v-model are inherited from the <wui-form-checkbox-group>.

Note: the unchecked-value prop does not affect the native <input>'s value attribute, because browsers don't include unchecked boxes in form submissions. To guarantee that one of two values is submitted in a native <form> submit (e.g. 'yes' or 'no'), use radio inputs instead. This is the same limitation that Vue has with native checkbox inputs.

Multiple checkboxes and accessibility

When binding multiple checkboxes together, you must set the name prop to the same value for all <wui-form-checkbox>s in the group individually or via the name prop of <wui-form-checkbox-group>. This will inform users of assistive technologies that the checkboxes are related and enables native browser keyboard navigation.

Whenever using multiple checkboxes, it is recommended that the checkboxes be placed in a <wui-form-group> component to associate a label with the entire group of checkboxes. See examples above.

Non custom check inputs (plain)

You can have <wui-form-checkbox-group> or <wui-form-checkbox> render a browser native checkbox input by setting the plain prop.

<template>
  <div>
    <wui-form-group
      label="Plain inline checkboxes"
      v-slot="{ ariaDescribedby }"
    >
      <wui-form-checkbox-group
        v-model="selected"
        :options="options"
        :aria-describedby="ariaDescribedby"
        plain
      ></wui-form-checkbox-group>
    </wui-form-group>

    <wui-form-group
      label="Plain stacked checkboxes"
      v-slot="{ ariaDescribedby }"
    >
      <wui-form-checkbox-group
        v-model="selected"
        :options="options"
        :aria-describedby="ariaDescribedby"
        plain
        stacked
      ></wui-form-checkbox-group>
    </wui-form-group>
  </div>
</template>

<script>
  export default {
    data() {
      return {
        selected: [], // Must be an array reference!
        options: [
          { text: "Orange", value: "orange" },
          { text: "Apple", value: "apple" },
          { text: "Pineapple", value: "pineapple" },
          { text: "Grape", value: "grape" },
        ],
      };
    },
  };
</script>

<!-- wui-form-checkbox-plain.vue -->

Note: The plain prop has no effect when button or buttons is set.

Contextual states

WUI includes validation styles for valid and invalid states on most form controls.

Generally speaking, you'll want to use a particular state for specific types of feedback:

• false or error (denotes invalid state) is great for when there's a blocking or required field. A user must fill in this field properly to submit the form.
• true or success (denotes valid state) is ideal for situations when you have per-field validation throughout
• warning (denotes invalid state) is great for when there's a field with a value which is not an error but might be a risky value in the context of the submitted data a form and want to encourage a user through the rest of the fields.
• null Displays no validation state (neither valid nor invalid)

To apply one of the contextual state icons on <wui-form-input>, set the state prop to false or error (for invalid), true or success (for valid), or null (no validation state).

Contextual state and validation example

<template>
  <div>
    <wui-form-checkbox-group
      v-model="value"
      :options="options"
      :state="state"
      name="checkbox-validation"
    >
      <wui-form-invalid-feedback :state="state"
        >Please select two</wui-form-invalid-feedback
      >
      <wui-form-valid-feedback :state="state"
        >Thank you</wui-form-valid-feedback
      >
    </wui-form-checkbox-group>
  </div>
</template>

<script>
  export default {
    data() {
      return {
        value: [],
        options: [
          { text: "First Check", value: "first" },
          { text: "Second Check", value: "second" },
          { text: "Third Check", value: "third" },
        ],
      };
    },
    computed: {
      state() {
        return this.value.length === 2;
      },
    },
  };
</script>

<!-- form-checkbox-validation.vue -->

Required constraint

When using individual <wui-form-checkbox> components (not in a <wui-form-checkbox-group>), and you want the checkbox(es) to be required in your form, you must provide a name on each <wui-form-checkbox> in order for the required constraint to work. All <wui-form-checkbox> components tied to the same v-model must have the same name.

The name is required in order for Assistive Technologies (such as screen readers, and keyboard only users) to know which checkboxes belong to the same form variable (the name also automatically enables native browser keyboard navigation), hence required will only work if name is set. <wui-form-checkbox-group> will automatically generate a unique input name if one is not provided on the group.

Autofocus

When the autofocus prop is set on <wui-form-checkbox>, the input will be auto-focused when it is inserted (i.e. mounted) into the document, or re-activated when inside a Vue <keep-alive> component. Note that this prop does not set the autofocus attribute on the input, nor can it tell when the input becomes visible.

Indeterminate (tri-state) support

Normally a checkbox input can only have two states: checked or unchecked. They can have any value, but they either submit that value (checked) or don't (unchecked) with a form submission (although WuiVue allows a value for the unchecked state on a single checkbox)

Visually, there are actually three states a checkbox can be in: checked, unchecked, or indeterminate.

The indeterminate state is visual only. The checkbox is still either checked or unchecked as a value. That means the visual indeterminate state masks the real value of the checkbox, so that better make sense in your UI!

<wui-form-checkbox> supports setting this visual indeterminate state via the indeterminate prop (defaults to false). Clicking the checkbox will clear its indeterminate state. The indeterminate prop can be synced to the checkbox's state by v-binding the indeterminate prop with the .sync modifier.

Note: indeterminate styling is not supported in button or switch mode, nor is it supported in <wui-form-checkbox-group> (multiple checkboxes).

Single Indeterminate checkbox:

<template>
  <div>
    <wui-form-checkbox v-model="checked" :indeterminate.sync="indeterminate">
      Click me to see what happens
    </wui-form-checkbox>

    <div class="mt-3">
      Checked: <strong>{ checked }</strong><br />
      Indeterminate: <strong>{ indeterminate }</strong>
    </div>

    <wui-button @click="toggleIndeterminate"
      >Toggle Indeterminate State</wui-button
    >
  </div>
</template>

<script>
  export default {
    data() {
      return {
        checked: true,
        indeterminate: true,
      };
    },
    methods: {
      toggleIndeterminate() {
        this.indeterminate = !this.indeterminate;
      },
    },
  };
</script>

<!-- wui-form-checkbox-indeterminate.vue -->

Indeterminate checkbox use-case example:

<template>
  <div>
    <wui-form-group>
      <template #label>
        <b>Choose your flavours:</b><br />
        <wui-form-checkbox
          v-model="allSelected"
          :indeterminate="indeterminate"
          aria-describedby="flavours"
          aria-controls="flavours"
          @change="toggleAll"
          :value="true"
          :unchecked-value="false"
        >
          { allSelected ? 'Un-select All' : 'Select All' }
        </wui-form-checkbox>
      </template>

      <template v-slot="{ ariaDescribedby }">
        <wui-form-checkbox-group
          id="flavors"
          v-model="selected"
          :options="flavours"
          :aria-describedby="ariaDescribedby"
          name="flavors"
          class="ml-4"
          aria-label="Individual flavours"
          stacked
        ></wui-form-checkbox-group>
      </wui-form-group>

      <div>
        Selected: <strong>{ selected }</strong><br />
        All Selected: <strong>{ allSelected }</strong><br />
        Indeterminate: <strong>{ indeterminate }</strong>
      </div>
    </template>
  </div>
</template>

<script>
  export default {
    data() {
      return {
        flavours: ['Orange', 'Grape', 'Apple', 'Lime', 'Very Berry'],
        selected: [],
        allSelected: false,
        indeterminate: false
      }
    },
    methods: {
      toggleAll() {
        this.selected = this.allSelected ? this.flavours.slice() : []
      }
    },
    watch: {
      selected(newValue, oldValue) {
        // Handle changes in individual flavour checkboxes
        if (newValue.length === 0) {
          this.indeterminate = false
          this.allSelected = false
        } else if (newValue.length === this.flavours.length) {
          this.indeterminate = false
          this.allSelected = true
        } else {
          this.indeterminate = true
          this.allSelected = false
        }
      }
    }
  }
</script>

<!-- wui-form-checkbox-indeterminate-multiple.vue -->

Note: Pay attention that plain checkbox (i.e. with prop plain) also supports indeterminate state on Windows/Linux/Mac/Android, but not on iOS.

Indeterminate state and accessibility

Not all screen readers will convey the indeterminate state to screen reader users. So it is recommended to provide some form of textual feedback to the user (possibly by via the .sr-only class) if the indeterminate state has special contextual meaning in your application.

Component reference

<wui-form-checkbox-group>

Component aliases

<wui-form-checkbox-group> can also be used via the following aliases:

• <wui-checkbox-group>
• <wui-check-group>

Properties

v-model

Slots

Events

<wui-form-checkbox>

Component aliases

<wui-form-checkbox> can also be used via the following aliases:

• <wui-checkbox>
• <wui-check>

Properties

v-model

Slots

Events