StackGenVis/frontend/node_modules/bootstrap-vue/src/components/form-input

Textual and Value inputs

Create various type inputs such as: text, password, number, url, email, search, range, date and more.

<template>
  <div>
    <b-form-input v-model="text" placeholder="Enter your name"></b-form-input>
    <div class="mt-2">Value: {{ text }}</div>
  </div>
</template>

<script>
  export default {
    data() {
      return {
        text: ''
      }
    }
  }
</script>

<!-- b-form-input.vue -->

Input type

<b-form-input> defaults to a text input, but you can set the type prop to one of the supported native browser HTML5 types: text, password, email, number, url, tel, search, date, datetime, datetime-local, month, week, time, range, or color.

<template>
  <b-container fluid>
    <b-row class="my-1" v-for="type in types" :key="type">
      <b-col sm="3">
        <label :for="`type-${type}`">Type <code>{{ type }}</code>:</label>
      </b-col>
      <b-col sm="9">
        <b-form-input :id="`type-${type}`" :type="type"></b-form-input>
      </b-col>
    </b-row>
  </b-container>
</template>

<script>
  export default {
    data() {
      return {
        types: [
          'text',
          'number',
          'email',
          'password',
          'search',
          'url',
          'tel',
          'date',
          'time',
          'range',
          'color'
        ]
      }
    }
  }
</script>

<!-- b-form-input-types.vue -->

If the type prop is set to an input type that is not supported (see above), a text input will be rendered and a console warning will be issued.

Caveats with input types:

• Not all browsers support all input types, nor do some types render in the same format across browser types/versions. Refer to caniuse.com.
• Browsers that do not support a particular type will fall back to a text input type (even though the rendered type attribute markup shows the requested type).
• No testing is performed to see if the requested input type is supported by the browser.
• Chrome lost support for datetime in version 26, Opera in version 15, and Safari in iOS 7. Instead of using datetime, since support should be deprecated, use date and time as two separate inputs.
• date and time inputs are native browser types, and are not a custom date/time picker.
• For date and time style inputs, where supported, the displayed value in the GUI may be different than what is returned by its value (i.e. ordering of year-month-date).
• Regardless of input type, the value is always returned as a string representation.
• v-model.lazy is not supported by <b-form-input> (nor any custom Vue component). Use the lazy prop instead.
• v-model modifiers .number and .trim can cause unexpected cursor jumps when the user is typing (this is a Vue issue with v-model on custom components). Avoid using these modifiers. Use the number or trim props instead.
• Older version of Firefox may not support readonly for range type inputs.
• Input types that do not support min, max and step (i.e. text, password, tel, email, url, etc) will silently ignore these values (although they will still be rendered on the input markup) if values are provided.

Caveats with predictive text entry and IME composition entry:

• When using predictive text auto-suggested words, the v-model will not update until the auto-suggested word is selected (or a space is typed). If an auto suggested word is not selected, the v-model will update with the current displayed text of the input when the input is blurred.
• When using IME composition (ie. Chinese, Japanese, etc), the v-model will not update until the IME composition is completed.

Range type input

Inputs with type range render using Bootstrap v4's .custom-range class. The track (the background) and thumb (the value) are both styled to appear the same across browsers.

Range inputs have implicit values for min and max of 0 and 100 respectively. You may specify new values for those using the min and max props.

<template>
  <div>
    <label for="range-1">Example range with min and max</label>
    <b-form-input id="range-1" v-model="value" type="range" min="0" max="5"></b-form-input>
    <div class="mt-2">Value: {{ value }}</div>
  </div>
</template>

<script>
  export default {
    data() {
      return {
        value: '2'
      }
    }
  }
</script>

<!-- b-form-input-range.vue -->

By default, range inputs "snap" to integer values. To change this, you can specify a step value. In the example below, we double the number of steps by using step="0.5".

<template>
  <div>
    <label for="range-2">Example range with step value</label>
    <b-form-input id="range-2" v-model="value" type="range" min="0" max="5" step="0.5"></b-form-input>
    <div class="mt-2">Value: {{ value }}</div>
  </div>
</template>

<script>
  export default {
    data() {
      return {
        value: '2'
      }
    }
  }
</script>

<!-- b-form-input-range-step.vue -->

Note: Range inputs (as do all input types) return their value as a string. You may need to convert the value to a native number by using Number(value), parseInt(value, 10), parseFloat(value), or use the number prop.

Note: Bootstrap v4 CSS does not include styling for range inputs inside input groups, nor validation styling on range inputs. However, BootstrapVue includes custom styling to handle these situations until styling is included in Bootstrap v4.

Control sizing

Set heights using the size prop to sm or lg for small or large respectively.

To control width, place the input inside standard Bootstrap grid column.

<b-container fluid>
  <b-row class="my-1">
    <b-col sm="2">
      <label for="input-small">Small:</label>
    </b-col>
    <b-col sm="10">
      <b-form-input id="input-small" size="sm" placeholder="Enter your name"></b-form-input>
    </b-col>
  </b-row>

  <b-row class="my-1">
    <b-col sm="2">
      <label for="input-default">Default:</label>
    </b-col>
    <b-col sm="10">
      <b-form-input id="input-default" placeholder="Enter your name"></b-form-input>
    </b-col>
  </b-row>

  <b-row class="my-1">
    <b-col sm="2">
      <label for="input-large">Large:</label>
    </b-col>
    <b-col sm="10">
      <b-form-input id="input-large" size="lg" placeholder="Enter your name"></b-form-input>
    </b-col>
  </b-row>
</b-container>

<!-- b-form-input-size.vue -->

Note: Input type range currently does not support control sizing unless it is placed inside a <b-input-group> which has its size prop set.

Note: The native HTML <input> attribute size (which sets a horizontal width on the <input> in characters) is not supported. Use styling, utility classes, or the layout rows (<b-row>) and columns (<b-col>) to set the desired width.

Contextual states

Bootstrap 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 (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 (denotes valid state) is ideal for situations when you have per-field validation throughout 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 <b-form-input>, set the state prop to false (for invalid), true (for valid), or null (no validation state).

<b-container fluid>
  <b-row class="my-1">
    <b-col sm="3">
      <label for="input-none">No State:</label>
    </b-col>
    <b-col sm="9">
      <b-form-input id="input-none" :state="null" placeholder="No validation"></b-form-input>
    </b-col>
  </b-row>

  <b-row class="my-1">
    <b-col sm="3">
      <label for="input-valid">Valid State:</label>
    </b-col>
    <b-col sm="9">
      <b-form-input id="input-valid" :state="true" placeholder="Valid input"></b-form-input>
    </b-col>
  </b-row>

  <b-row class="my-1">
    <b-col sm="3">
      <label for="input-invalid">Invalid State:</label>
    </b-col>
    <b-col sm="9">
      <b-form-input id="input-invalid" :state="false" placeholder="Invalid input"></b-form-input>
    </b-col>
  </b-row>
</b-container>

<!-- b-form-input-states.vue -->

Live Example

<template>
  <div role="group">
    <label for="input-live">Name:</label>
    <b-form-input
      id="input-live"
      v-model="name"
      :state="nameState"
      aria-describedby="input-live-help input-live-feedback"
      placeholder="Enter your name"
      trim
    ></b-form-input>

    <!-- This will only be shown if the preceding input has an invalid state -->
    <b-form-invalid-feedback id="input-live-feedback">
      Enter at least 3 letters
    </b-form-invalid-feedback>

    <!-- This is a form text block (formerly known as help block) -->
    <b-form-text id="input-live-help">Your full name.</b-form-text>
  </div>
</template>

<script>
  export default {
    computed: {
      nameState() {
        return this.name.length > 2 ? true : false
      }
    },
    data() {
      return {
        name: ''
      }
    }
  }
</script>

<!-- b-form-input-states-feedback.vue -->

Tip: Use the <b-form-group> component to automatically generate markup similar to above.

Conveying contextual state to assistive technologies and colorblind users

Using these contextual states to denote the state of a form control only provides a visual, color-based indication, which will not be conveyed to users of assistive technologies - such as screen readers - or to colorblind users.

Ensure that an alternative indication of state is also provided. For instance, you could include a hint about state in the form control's <label> text itself, or by providing an additional help text block.

ARIA aria-invalid attribute

Specifically for assistive technologies, invalid form controls can also be assigned an aria-invalid="true" attribute.

When <b-form-input> has an invalid contextual state (i.e. state is false) you may also want to set the <b-form-input> prop aria-invalid to true, or to one of the supported values:

• false: Convey no errors detected (default)
• true (or 'true'): Convey that the value has failed validation.
• 'grammar' Convey that a grammatical error has been detected.
• 'spelling' Convey that a spelling error has been detected.

If aria-invalid is not explicitly set and state is set to false, then the aria-invalid attribute on the input will automatically be set to 'true';

Formatter support

<b-form-input> optionally supports formatting by passing a function reference to the formatter prop.

Formatting (when a formatter function is supplied) occurs when the control's native input and change events fire. You can use the boolean prop lazy-formatter to restrict the formatter function to being called on the control's native blur event.

The formatter function receives two arguments: the raw value of the input element, and the native event object that triggered the format (if available).

The formatter function should return the formatted value as a string.

Formatting does not occur if a formatter is not provided.

<template>
  <div>
    <b-form-group
      class="mb-0"
      label="Text input with formatter (on input)"
      label-for="input-formatter"
      description="We will convert your name to lowercase instantly"
    >
      <b-form-input
        id="input-formatter"
        v-model="text1"
        placeholder="Enter your name"
        :formatter="formatter"
      ></b-form-input>
    </b-form-group>
    <p><b>Value:</b> {{ text1 }}</p>

    <b-form-group
      class="mb-0"
      label="Text input with lazy formatter (on blur)"
      label-for="input-lazy"
      description="This one is a little lazy!"
    >
      <b-form-input
        id="input-lazy"
        v-model="text2"
        placeholder="Enter your name"
        lazy-formatter
        :formatter="formatter"
      ></b-form-input>
    </b-form-group>
    <p class="mb-0"><b>Value:</b> {{ text2 }}</p>
  </div>
</template>

<script>
  export default {
    data() {
      return {
        text1: '',
        text2: ''
      }
    },
    methods: {
      formatter(value) {
        return value.toLowerCase()
      }
    }
  }
</script>

<!-- b-form-input-formatter.vue -->

Note: When using a non-text-like input (i.e. color, range, date, number, email etc), ensure that your formatter function returns the value in the expected format for the input type. The formatter must return the value as a string.

Note: With non-lazy formatting, if the cursor is not at the end of the input value, the cursor may jump to the end after a character is typed. You can use the provided event object and the event.target to access the native input's selection methods and properties to control where the insertion point is. This is left as an exercise for the reader.

Readonly plain text

If you want to have <b-form-input readonly> elements in your form styled as plain text, set the plaintext prop (no need to set readonly) to remove the default form field styling and preserve the correct margin and padding.

The plaintext option is not supported by input types color or range.

Disabling mousewheel events on numeric-like inputs

On some browsers, scrolling the mousewheel while a numeric-like input is focused will increment or decrement the input's value. To disable this browser feature, just set the no-wheel prop to true.

Datalist support

Datalists are a native HTML tag <datalist> that contains a list of <option> tags. By assigning an ID to the datalist tag, the list can be references from a text input by adding a list attribute.

This gives the input the behavior of a combo box or auto-complete, allowing existing values to be chosen, or new values to be entered.

<template>
  <b-form-input list="my-list-id"></b-form-input>

  <datalist id="my-list-id">
    <option>Manual Option</option>
    <option v-for="size in sizes">{{ size }}</option>
  </datalist>
</template>

<script>
  export default {
    data() {
      return {
        sizes: ['Small', 'Medium', 'Large', 'Extra Large']
      }
    }
  }
</script>

<!-- b-form-input-datalist.vue -->

BootstrapVue provides the form helper component <b-form-datalist> for quickly creating a <datalist> from an array of options.

Notes:

• Datalists work in conjunction with the browser's built in auto-complete, displaying datalist options first, followed by auto-complete options. To only display datalist options, set autocomplete="off" on <b-form-input>.
• Datalists cannot be applied to input fields with type password, range or color.
• Not all browsers fully support <datalist> and implementations can be buggy. It is recommended that datalists be treated as an enhancement and not be relied upon at this time. Check Can I Use for full support details on all browsers.

v-model modifiers

Vue does not officially support .lazy, .trim, and .number modifiers on the v-model of custom component based inputs, and may generate a bad user experience. Avoid using Vue's native modifiers.

To get around this, <b-form-input> has three boolean props trim, number, and lazy which emulate the native Vue v-model modifiers .trim and .number and .lazy respectively. The lazy prop will update the v-model on change/blurevents.

Notes:

• The number prop takes precedence over the trim prop (i.e. trim will have no effect when number is set).
• When using the number prop, and if the value can be parsed as a number (via parseFloat) it will return a value of type Number to the v-model, otherwise the original input value is returned as type String. This is the same behaviour as the native .number modifier.
• The trim and number modifier props do not affect the value returned by the input or change events. These events will always return the string value of the content of <textarea> after optional formatting (which may not match the value returned via the v-model update event, which handles the modifiers).

Debounce support

As an alternative to the lazy modifier prop, <b-form-input> optionally supports debouncing user input, updating the v-model after a period of idle time from when the last character was entered by the user (or a change event occurs). If the user enters a new character (or deletes characters) before the idle timeout expires, the timeout is re-started.

To enable debouncing, set the prop debounce to any integer greater than zero. The value is specified in milliseconds. Setting debounce to 0 will disable debouncing.

Note: debouncing will not occur if the lazy prop is set.

<template>
  <div>
    <b-form-input v-model="value" type="text" debounce="500"></b-form-input>
    <div class="mt-2">Value: "{{ value }}"</div>
  </div>
</template>

<script>
  export default {
    data() {
      return {
        value: ''
      }
    }
  }
</script>

<!-- b-form-input-debounce.vue -->

Autofocus

When the autofocus prop is set, 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.

Native and custom events

All native events (other than the custom input and change events) are supported, without the need for the .native modifier.

The custom input and change events receive a single argument of the current value (after any formatting has been applied), and are triggered by user interaction.

The custom update event is passed the input value, and is emitted whenever the v-model needs updating (it is emitted before input, change. and blur as needed).

You can always access the native input and change events by using the .native modifier.

Exposed input properties and methods

<b-form-input> exposes several of the native input element's properties and methods on the component reference (i.e. assign a ref to your <b-form-input ref="foo" ...> and use this.$refs['foo'].propertyName or this.$refs['foo'].methodName(...)).

Input properties

Property	Notes
.selectionStart	Read/Write
.selectionEnd	Read/Write
.selectionDirection	Read/Write
.validity	Read only
.validationMessage	Read only
.willValidate	Read only

Input methods

Method	Notes
.focus()	Focus the input
.blur()	Remove focus from the input
.select()	Selects all text within the input
.setSelectionRange()
.setRangeText()
.setCustomValidity()
.checkValidity()
.reportValidity()

Refer to https://developer.mozilla.org/en-US/docs/Web/API/HTMLInputElement for more information on these methods and properties. Support will vary based on input type.

Using HTML5 <input> as an alternative

If you just need a simple input with basic bootstrap styling, you can simply use the following:

<template>
  <div>
    <input v-model="value" type="text" class="form-control">
    <br>
    <p>Value: "{{ value }}"</p>
  </div>
</template>

<script>
  export default {
    data() {
      return {
        value: ''
      }
    }
  }
</script>

<!-- native-input.vue -->