StackGenVis/frontend/node_modules/bootstrap-vue/src/components/form-tags/README.md

Form tags

Lightweight custom tagged input form control, with options for customized interface rendering, duplicate tag detection and optional tag validation.

Tags are arrays of short strings, used in various ways such as assigning categories. Use the default user interface, or create your own custom interface via the use of the default scoped slot.

The tagged input was added in BootstrapVue release v2.2.0.

Basic usage

Tags will have any leading and tailing whitespace removed, and duplicate tags are not permitted. Tags that contain spaces are permitted by default.

Tags are added by clicking the Add button, pressing the ENTER key or optionally when the change event fires on the new tag input (i.e. when focus moves from the input). The Add button will only appear when the user has entered a new tag value.

Default render:

<template>
  <div>
    <label for="tags-basic">Type a new tag and press enter</label>
    <b-form-tags input-id="tags-basic" v-model="value" class="mb-2"></b-form-tags>
    <p>Value: {{ value }}</p>
  </div>
</template>

<script>
  export default {
    data() {
      return {
        value: ['apple', 'orange']
      }
    }
  }
</script>

<!-- form-tags-example.vue -->

You can disable adding a new tag when pressing ENTER via the no-add-on-enter prop, and enable adding a tag on the input's change event via the add-on-change prop.

Tag creation using separators

To auto create tags when a separator character is typed (i.e. SPACE, ,, etc), set the separator prop to the character that will trigger the tag to be added. If multiple separator characters are needed, then include them as a single string (i.e. ' ,;'), or an array of characters (i.e. [' ', ',', ';']), which will trigger a new tag to be added when SPACE, ,, or ; are typed). Separators must be a single character.

The following example will auto create a tag when SPACE, ,, or ; are typed:

<template>
  <div>
    <label for="tags-separators">Enter tags separated by space, comma or semicolon</label>
    <b-form-tags
      input-id="tags-separators"
      v-model="value"
      separator=" ,;"
      placeholder="Enter new tags separated by space, comma or semicolon"
      no-add-on-enter
      class="mb-2"
    ></b-form-tags>
    <p>Value: {{ value }}</p>
  </div>
</template>

<script>
  export default {
    data() {
      return {
        value: ['one', 'two']
      }
    }
  }
</script>

<!-- form-tags-separator.vue -->

Last tag removal via backspace keypress

When the prop remove-on-delete is set, and the user presses BACKSPACE (or DEL) and the input value is empty, the last tag in the tag list will be removed.

<template>
  <div>
    <label for="tags-remove-on-delete">Enter new tags separated by space</label>
    <b-form-tags
      input-id="tags-remove-on-delete"
      :input-attrs="{ 'aria-describedby': 'tags-remove-on-delete-help' }"
      v-model="value"
      separator=" "
      placeholder="Enter new tags separated by space"
      remove-on-delete
      no-add-on-enter
      class="mb-2"
    ></b-form-tags>
    <b-form-text id="tags-remove-on-delete-help">
      Press <kbd>BACKSPACE</kbd> to remove the last tag entered
    </b-form-text>
    <p>Value: {{ value }}</p>
  </div>
</template>

<script>
  export default {
    data() {
      return {
        value: ['apple', 'orange', 'grape']
      }
    }
  }
</script>

<!-- form-tags-remove-on-delete.vue -->

Styling Options

Several props are available to alter the basic styling of the default tagged interface:

Prop	Description
tag-pills	Renders the tags with the appearance of pills
tag-variant	Applies one of the Bootstrap contextual variant theme colors to the tags
size	Set the size of the component's appearance. 'sm', 'md' (default), or 'lg'
placeholder	The placeholder text for the new tag input element
state	Sets the contextual state of the control. Set to true (for valid), false (for invalid), or null
disabled	Places the component in a disabled state

For additional props, see the component reference section at the bottom of this page.

The focus and validation state styling of the component relies upon BootstrapVue's custom CSS.

<template>
  <div>
    <label for="tags-pills">Enter tags</label>
    <b-form-tags
      input-id="tags-pills"
      v-model="value"
      tag-variant="primary"
      tag-pills
      size="lg"
      separator=" "
      placeholder="Enter new tags separated by space"
      class="mb-2"
    ></b-form-tags>
    <p>Value: {{ value }}</p>
  </div>
</template>

<script>
  export default {
    data() {
      return {
        value: ['apple', 'orange', 'grape']
      }
    }
  }
</script>

<!-- form-tags-style-options.vue -->

Using with native browser <form> submission

The value of the tagged input will not be submitted via standard form action unless you provide a name via the name prop. When a name is provided, <b-form-tags> will create a hidden <input> for each tag. The hidden input will have the name attribute set to the value of the name prop.

The hidden inputs will also be generated when using custom rendering (when the name prop is set).

Tag validation

By default, <b-form-tags> detects when the user is attempting to enter a (case-sensitive) duplicate tag, and will provide integrated feedback to the user.

You can optionally provide a tag validator method via the tag-validator prop. The validator function will receive one argument which is the tag being added, and should return either true if the tag passes validation and can be added, or false if the tag fails validation (in which case it is not added to the array of tags). integrated feedback will be provided to the user listing the invalid tag(s) that could not be added.

Tag validation occurs only for tags added via user input. Changes to the tags via the v-model are not validated.

<template>
  <div>
    <b-form-group :state="state" label="Tags validation example" label-for="tags-validation">
      <b-form-tags
        input-id="tags-validation"
        :input-attrs="{ 'aria-describedby': 'tags-validation-help' }"
        v-model="tags"
        :state="state"
        :tag-validator="tagValidator"
        separator=" "
      ></b-form-tags>
      <!-- The following slots are for b-form-group -->
      <template v-slot:invalid-feedback>
        You must provide at least 3 tags and no more than 8
      </template>
      <template v-slot:description>
        <div id="tags-validation-help">
         Tags must be 3 to 5 characters in length and all lower
         case. Enter tags separated by spaces or press enter.
        </div>
      </template>
    </b-form-group>
  </div>
</template>

<script>
  export default {
    data() {
      return {
        tags: [],
        dirty: false
      }
    },
    computed: {
      state() {
        // Overall component validation state
        return this.dirty ? (this.tags.length > 2 && this.tags.length < 9) : null
      }
    },
    watch: {
      tags(newVal, oldVal) {
        // Set the dirty flag on first change to the tags array
        this.dirty = true
      }
    },
    methods: {
      tagValidator(tag) {
        // Individual tag validator function
        return tag === tag.toLowerCase() && tag.length > 2 && tag.length < 6
      }
    }
  }
</script>

<!-- b-form-tags-validation-feedback.vue -->

Detecting new, invalid, and duplicate tags

The event tag-state will be emitted whenever new tags are entered into the new tag input element, tags that do not pass validation, or duplicate tags are detected. The event handler will receive three arrays as its arguments:

• validTags (tags that pass validation)
• invalidTags (tags that do not pass validation)
• duplicateTags (tags that would be a duplicate of existing or validTags).

The event will be emitted only when the new tag input changes (characters are entered that would be considered part of a tag), or when the user attempts to add a tag (i.e. via ENTER, clicking the Add button, or entering a separator). The three arrays will be empty when the user clears the new tag input element (or contains just spaces).

If you are providing your own feedback for duplicate and invalid tags (via the use of the tag-state event) outside of the <b-form-tags> component, you can disable the built in duplicate and invalid messages by setting the props duplicate-tag-text and invalid-tag-text (respectively) to either an empty string ('') or null.

<template>
  <div>
    <label for="tags-state-event">Enter tags</label>
    <b-form-tags
      input-id="tags-state-event"
      v-model="tags"
      :tag-validator="validator"
      placeholder="Enter tags (3-5 characters) separated by space"
      separator=" "
      @tag-state="onTagState"
    ></b-form-tags>
    <p class="mt-2">Tags: {{ tags }}</p>
    <p>Event values:</p>
    <ul>
        <li>validTags: {{ validTags }}</li>
        <li>invalidTags: {{ invalidTags }}</li>
        <li>duplicateTags: {{ duplicateTags }}</li>
    </ul>
  </div>
</template>

<script>
  export default {
    data() {
      return {
        tags: [],
        validTags: [],
        invalidTags: [],
        duplicateTags: []
      }
    },
    methods: {
      onTagState(valid, invalid, duplicate) {
        this.validTags = valid
        this.invalidTags = invalid
        this.duplicateTags = duplicate
      },
      validator(tag) {
        return tag.length > 2 && tag.length < 6
      }
    }
  }
</script>

<!-- b-form-tags-tags-state-event.vue -->

Custom rendering with default scoped slot

If you fancy a different look and feel for the tags control, you can provide your own custom rendering via the default scoped slot. You can either create your own tags, or use our helper <b-form-tag> component.

Scope properties

The default scoped slot provides numerous properties and methods for use in rendering your custom interface. Not all properties or methods are required to generate your interface.

The default slot scope properties are as follows:

Property	Type	Description
tags	Array	Array of current tag strings
inputAttrs	Object	Object of attributes to apply to the new tag input element via v-bind="inputAttrs". See below for details
inputType	String	v2.3.0+ Type of input to render (normalized version of prop input-type)
inputHandlers	Object	Object of event handlers to apply to the new tag input element via v-on="inputHandlers". See below for details
removeTag	Function	Method to remove a tag. Accepts one argument which is the tag value to remove
addTag	Function	Method to add a new tag. Assumes the tag is the value of the input, but optionally accepts one argument which is the tag value to be added
inputId	String	ID to add to the new tag input element. Defaults to prop input-id. If not provided a unique ID is auto-generated. Also available via 'inputAttrs.id'
isInvalid	Boolean	true if the user input contains invalid tag(s)
invalidTags	Array	Array of the invalid tag(s) the user has entered
isDuplicate	Boolean	true if the user input contains duplicate tag(s)
duplicateTags	Array	Array of the duplicate tag(s) the user has entered
disableAddButton	Boolean	Will be true if the tag(s) in the input cannot be added (all invalid and/or duplicates)
disabled	Boolean	true if the component is in the disabled state. Value of the disabled prop
state	Boolean	The contextual state of the component. Value of the state prop. Possible values are true, false or null
size	String	The value of the size prop
separator	String	The value of the separator prop
placeholder	String	The value of the placeholder prop
tagRemoveLabel	String	Value of the tag-remove-label prop. Used as the aria-label attribute on the remove button of tags
tagVariant	String	The value of the tag-variant prop
tagClass	String, Array, or Object	The value of the tag-variant prop. Class (or classes) to apply to the tag elements
addButtonText	String	The value of the add-button-text prop
addButtonVariant	String	The value of the add-button-variant prop

inputAttrs object properties

The inputAttrs object contains attributes to bind (v-bind) to the new tag input element.

Property	Type	Description
id	String	the id attribute for the new tag input
value	String	The value attribute for the new tag input
disabled	Boolean	The disabled attribute for the new tag input. Value of the disabled prop
form	String	The form attribute for the new tag input. Value of the form prop

The inputAttrs object will also include any attributes set via the input-attrs prop. Note that the above attributes take precedence over any of the same attributes specified in the input-attrs prop.

inputHandlers object properties

The inputHandlers object contains event handlers to bind (v-on) to the new tag input element.

Property	Type	Description
input	Function	Event handler for the input element input event. Accepts a single argument of either an event object or a string. Updates the internal v-model for the new tag input element
change	Function	Event handler for the input element change event. Accepts a single argument of either an event object or a string. Change will trigger adding the tag.
keydown	Function	Event handler for the input element keydown ENTER and DEL events. Accepts a single argument which is the native keydown event object

The change handler, when needed, must be enabled via the add-on-change prop, otherwise it is a noop method.

Using native browser inputs

The scope contains attributes and event handlers that can be directly bound to native <input> or <select> elements.

The following example includes the suggested ARIA attributes and roles needed for screen-reader support.

<template>
  <div>
    <b-form-tags v-model="value" no-outer-focus class="mb-2">
      <template v-slot="{ tags, inputAttrs, inputHandlers, addTag, removeTag }">
        <b-input-group aria-controls="my-custom-tags-list">
          <input
            v-bind="inputAttrs"
            v-on="inputHandlers"
            placeholder="New tag - Press enter to add"
            class="form-control">
          <b-input-group-append>
            <b-button @click="addTag()" variant="primary">Add</b-button>
          </b-input-group-append>
        </b-input-group>
        <ul
          id="my-custom-tags-list"
          class="list-unstyled d-inline-flex flex-wrap mb-0"
          aria-live="polite"
          aria-atomic="false"
          aria-relevant="additions removals"
        >
          <!-- Always use the tag value as the :key, not the index! -->
          <!-- Otherwise screen readers will not read the tag
               additions and removals correctly -->
          <b-card
            v-for="tag in tags"
            :key="tag"
            :id="`my-custom-tags-tag_${tag.replace(/\s/g, '_')}_`"
            tag="li"
            class="mt-1 mr-1"
            body-class="py-1 pr-2 text-nowrap"
          >
            <strong>{{ tag }}</strong>
            <b-button
              @click="removeTag(tag)"
              variant="link"
              size="sm"
              :aria-controls="`my-custom-tags-tag_${tag.replace(/\s/g, '_')}_`"
            >remove</b-button>
          </b-card>
        </ul>
      </template>
    </b-form-tags>
  </div>
</template>

<script>
  export default {
    data() {
      return {
        value: ['apple', 'orange', 'banana', 'pear', 'peach']
      }
    }
  }
</script>

<!-- form-tags-custom-native.vue -->

Using custom form components

The scope contains attributes and event handlers that can be directly bound to most custom inputs or select components (the event handlers accept either a string tag value or a native event object). Any component that emits input as characters are typed, and (optionally) emits change when the input value changes (i.e on blur or select), and uses the prop value as the v-model, should work without modification.

In this example, we are using the <b-form-tag> helper component, but feel free to render tags using standard HTML or components.

<template>
  <div>
    <b-form-tags v-model="value" no-outer-focus class="mb-2">
      <template v-slot="{ tags, inputAttrs, inputHandlers, tagVariant, addTag, removeTag }">
        <b-input-group class="mb-2">
          <b-form-input
            v-bind="inputAttrs"
            v-on="inputHandlers"
            placeholder="New tag - Press enter to add"
            class="form-control"
          ></b-form-input>
          <b-input-group-append>
            <b-button @click="addTag()" variant="primary">Add</b-button>
          </b-input-group-append>
        </b-input-group>
        <div class="d-inline-block" style="font-size: 1.5rem;">
          <b-form-tag
            v-for="tag in tags"
            @remove="removeTag(tag)"
            :key="tag"
            :title="tag"
            :variant="tagVariant"
            class="mr-1"
          >{{ tag }}</b-form-tag>
        </div>
      </template>
    </b-form-tags>
  </div>
</template>

<script>
  export default {
    data() {
      return {
        value: ['apple', 'orange', 'banana']
      }
    }
  }
</script>

<!-- form-tags-custom-components-input.vue -->

The following is an example of using a custom select component for choosing from a pre-defined set of tags:

<template>
  <div>
    <b-form-group label="Tagged input using select">
      <!-- prop `add-on-change` is needed to enable adding tags vie the `change` event -->
      <b-form-tags v-model="value" size="lg" add-on-change no-outer-focus class="mb-2">
        <template v-slot="{ tags, inputAttrs, inputHandlers, disabled, removeTag }">
          <ul v-if="tags.length > 0" class="list-inline d-inline-block mb-2">
            <li v-for="tag in tags" :key="tag" class="list-inline-item">
              <b-form-tag
                @remove="removeTag(tag)"
                :title="tag"
                :disabled="disabled"
                variant="info"
              >{{ tag }}</b-form-tag>
            </li>
          </ul>
          <b-form-select
            v-bind="inputAttrs"
            v-on="inputHandlers"
            :disabled="disabled || availableOptions.length === 0"
            :options="availableOptions"
          >
            <template v-slot:first>
              <!-- This is required to prevent bugs with Safari -->
              <option disabled value="">Choose a tag...</option>
            </template>
          </b-form-select>
        </template>
      </b-form-tags>
    </b-form-group>
  </div>
</template>

<script>
  export default {
    data() {
      return {
        options: ['Apple', 'Orange', 'Banana', 'Lime', 'Peach', 'Chocolate', 'Strawberry'],
        value: []
      }
    },
    computed: {
      availableOptions() {
        return this.options.filter(opt => this.value.indexOf(opt) === -1)
      }
    }
  }
</script>

<!-- b-form-tags-components-select.vue -->

If the custom input is using custom event names that mimic input and change, and/or needs the .native modifier for keydown, you can do something similar to below to bind the event handlers:

<template v-slot:default="{ inputAttrs, inputHandlers, removeTag, tags }">
  <custom-input
    :id="inputAttrs.id"
    :vistom-value-prop="inputAttrs.value"
    @custom-input-event="inputHandlers.input($event)"
    @custom-change-event="inputHandlers.change($event)"
    @keydown.native="inputHandlers.keydown($event)"
  ></custom-input>
  <template v-for="tag in tags">
    <!-- Your custom tag list here -->
  </template>
</template>

The inputHandlers.input handler must be bound to an event that updates with each character entered by the user for the as-you-type tag validation to work.

Advanced custom rendering usage

In situations where the inputHandlers will not work with your custom input, or if you need greater control over tag creation, you can take advantage of the additional properties provided via the default slot's scope.

<template>
  <div>
    <b-form-checkbox switch size="lg" v-model="disabled">Disable</b-form-checkbox>
    <b-form-tags
      v-model="value"
      @input="resetInputValue()"
      tag-variant="success"
      class="mb-2 mt-2"
      :disabled="disabled"
      no-outer-focus
      placeholder="Enter a new tag value and click Add"
      :state="state"
    >
      <template v-slot="{tags, inputId, placeholder, disabled, addTag, removeTag }">
        <b-input-group>
          <!-- Always bind the id to the input so that it can be focused when needed -->
          <b-form-input
            v-model="newTag"
            :id="inputId"
            :placeholder="placeholder"
            :disabled="disabled"
            :formatter="formatter"
          ></b-form-input>
          <b-input-group-append>
            <b-button @click="addTag(newTag)" :disabled="disabled" variant="primary">Add</b-button>
          </b-input-group-append>
        </b-input-group>
        <b-form-invalid-feedback :state="state">
          Duplicate tag value cannot be added again!
        </b-form-invalid-feedback>
        <ul v-if="tags.length > 0" class="mb-0">
          <li v-for="tag in tags" :key="tag" :title="`Tag: ${tag}`" class="mt-2">
            <span  class="d-flex align-items-center">
              <span class="mr-2">{{ tag }}</span>
              <b-button
                :disabled="disabled"
                size="sm"
                variant="outline-danger"
                @click="removeTag(tag)"
              >
                remove tag
              </b-button>
            </span>
          </li>
        </ul>
        <b-form-text v-else>
          There are no tags specified. Add a new tag above.
        </b-form-text>
      </template>
    </b-form-tags>
  </div>
</template>

<script>
  export default {
    data() {
      return {
        newTag: '',
        disabled: false,
        value: []
      }
    },
    computed: {
      state() {
        // Return false (invalid) if new tag is a duplicate
        return this.value.indexOf(this.newTag.trim()) > -1 ? false : null
      }
    },
    methods: {
      resetInputValue() {
        this.newTag = ''
      },
      formatter(value) {
        return value.toUpperCase()
      }
    }
  }
</script>

<!-- form-tags-custom-components-advanced.vue -->

The following is an example of using the <b-dropdown> component for choosing or searching from a pre-defined set of tags:

<template>
  <div>
    <b-form-group label="Tagged input using dropdown">
      <b-form-tags v-model="value" no-outer-focus class="mb-2">
        <template v-slot="{ tags, disabled, addTag, removeTag }">
          <ul v-if="tags.length > 0" class="list-inline d-inline-block mb-2">
            <li v-for="tag in tags" :key="tag" class="list-inline-item">
              <b-form-tag
                @remove="removeTag(tag)"
                :title="tag"
                :disabled="disabled"
                variant="info"
              >{{ tag }}</b-form-tag>
            </li>
          </ul>

          <b-dropdown size="sm" variant="outline-secondary" block menu-class="w-100">
            <template v-slot:button-content>
              <b-icon icon="tag-fill"></b-icon> Choose tags
            </template>
            <b-dropdown-form @submit.stop.prevent="() => {}">
              <b-form-group
                label-for="tag-search-input"
                label="Search tags"
                label-cols-md="auto"
                class="mb-0"
                label-size="sm"
                :description="searchDesc"
                :disabled="disabled"
              >
                <b-form-input
                  v-model="search"
                  id="tag-search-input"
                  type="search"
                  size="sm"
                  autocomplete="off"
                 ></b-form-input>
              </b-form-group>
            </b-dropdown-form>
            <b-dropdown-divider></b-dropdown-divider>
            <b-dropdown-item-button
              v-for="option in availableOptions"
              :key="option"
              @click="onOptionClick({ option, addTag })"
            >
              {{ option }}
            </b-dropdown-item-button>
            <b-dropdown-text v-if="availableOptions.length === 0">
              There are no tags available to select
            </b-dropdown-text>
          </b-dropdown>
        </template>
      </b-form-tags>
    </b-form-group>
  </div>
</template>

<script>
  export default {
    data() {
      return {
        options: ['Apple', 'Orange', 'Banana', 'Lime', 'Peach', 'Chocolate', 'Strawberry'],
        search: '',
        value: []
      }
    },
    computed: {
      criteria() {
        // Compute the search criteria
        return this.search.trim().toLowerCase()
      },
      availableOptions() {
        const criteria = this.criteria
        // Filter out already selected options
        const options = this.options.filter(opt => this.value.indexOf(opt) === -1)
        if (criteria) {
          // Show only options that match criteria
          return options.filter(opt => opt.toLowerCase().indexOf(criteria) > -1);
        }
        // Show all options available
        return options
      },
      searchDesc() {
        if (this.criteria && this.availableOptions.length === 0) {
          return 'There are no tags matching your search criteria'
        }
        return ''
      }
    },
    methods: {
      onOptionClick({ option, addTag }) {
        addTag(option)
        this.search = ''
      }
    }
  }
</script>

<!-- b-form-tags-dropdown-example.vue -->

Creating wrapper components

You can easily create a custom wrapper component with your preferred rendering style as follows:

<template>
  <b-form-tags :value="value" @input="$emit('input', $event)">
    <template v-slot="{ tags, addTag, removeTag, inputAttrs, inputHandlers }">
     <!-- Place your custom rendering here -->
    </template>
  </b-form-tags>
</template>

<script>
  import { BFormTags } from 'bootstrap-vue'

  export default {
    name: 'MyCustomTags",
    components: { BFormTags },
    model: {
      prop: 'value',
      event: 'input'
    },
    props: {
      value: {
        type: Array,
        default: () => []
      }
    }
  }
</script>

<b-form-tag> helper component

BootstrapVue provides the helper component <b-form-tag>, for use with the default scoped slot of <b-form-tags>. The component is based upon <b-badge> and <b-button-close>.

<b-form-tag> supports the same variants as <b-badge> and also supports pill styling. Sizing is based on the containing element's font-size.

The remove event is emitted when the <b-form-tag> remove button is clicked.

Tags that are too wide for their parent container will automatically have their text content truncated with an ellipsis. For this reason, it is always good practice to supply a title via the title prop when using the default slot of <b-form-tag> for the tag content.

Note <b-form-tag> requires BootstrapVue's custom CSS/SCSS for proper styling.