paper-textarea.js

/**
@license
Copyright (c) 2015 The Polymer Project Authors. All rights reserved.
This code may only be used under the BSD style license found at
http://polymer.github.io/LICENSE.txt The complete set of authors may be found at
http://polymer.github.io/AUTHORS.txt The complete set of contributors may be
found at http://polymer.github.io/CONTRIBUTORS.txt Code distributed by Google as
part of the polymer project is also subject to an additional IP rights grant
found at http://polymer.github.io/PATENTS.txt
*/
import '@polymer/polymer/polymer-legacy.js';
import '@polymer/iron-autogrow-textarea/iron-autogrow-textarea.js';
import './paper-input-char-counter.js';
import './paper-input-container.js';
import './paper-input-error.js';

import {IronFormElementBehavior} from '@polymer/iron-form-element-behavior/iron-form-element-behavior.js';
import {Polymer} from '@polymer/polymer/lib/legacy/polymer-fn.js';
import {html} from '@polymer/polymer/lib/utils/html-tag.js';

import {PaperInputBehavior} from './paper-input-behavior.js';

/*
`<paper-textarea>` is a multi-line text field with Material Design styling.

    <paper-textarea label="Textarea label"></paper-textarea>

See `Polymer.PaperInputBehavior` for more API docs.

### Validation

Currently only `required` and `maxlength` validation is supported.

### Styling

See `Polymer.PaperInputContainer` for a list of custom properties used to
style this element.
*/
Polymer({
  /** @override */
  _template: html`
    <style>
      :host {
        display: block;
      }

      :host([hidden]) {
        display: none !important;
      }

      label {
        pointer-events: none;
      }
    </style>

    <paper-input-container no-label-float$="[[noLabelFloat]]" always-float-label="[[_computeAlwaysFloatLabel(alwaysFloatLabel,placeholder)]]" auto-validate$="[[autoValidate]]" disabled$="[[disabled]]" invalid="[[invalid]]">

      <label hidden$="[[!label]]" aria-hidden="true" for$="[[_inputId]]" slot="label">[[label]]</label>

      <iron-autogrow-textarea class="paper-input-input" slot="input" id$="[[_inputId]]" aria-labelledby$="[[_ariaLabelledBy]]" aria-describedby$="[[_ariaDescribedBy]]" bind-value="{{value}}" invalid="{{invalid}}" validator$="[[validator]]" disabled$="[[disabled]]" autocomplete$="[[autocomplete]]" autofocus$="[[autofocus]]" inputmode$="[[inputmode]]" name$="[[name]]" placeholder$="[[placeholder]]" readonly$="[[readonly]]" required$="[[required]]" minlength$="[[minlength]]" maxlength$="[[maxlength]]" autocapitalize$="[[autocapitalize]]" rows$="[[rows]]" max-rows$="[[maxRows]]" on-change="_onChange"></iron-autogrow-textarea>

      <template is="dom-if" if="[[errorMessage]]">
        <paper-input-error aria-live="assertive" slot="add-on">[[errorMessage]]</paper-input-error>
      </template>

      <template is="dom-if" if="[[charCounter]]">
        <paper-input-char-counter slot="add-on"></paper-input-char-counter>
      </template>

    </paper-input-container>
`,

  is: 'paper-textarea',

  behaviors: [
    PaperInputBehavior,
    IronFormElementBehavior,
  ],

  properties: {
    _ariaLabelledBy: {
      observer: '_ariaLabelledByChanged',
      type: String,
    },

    _ariaDescribedBy: {
      observer: '_ariaDescribedByChanged',
      type: String,
    },

    value: {
      // Required for the correct TypeScript type-generation
      type: String,
    },

    /**
     * The initial number of rows.
     * @type {number}
     * @default 1
     */
    rows: {
      type: Number,
      value: 1,
    },

    /**
     * The maximum number of rows this element can grow to until it
     * scrolls. 0 means no maximum.
     * @type {number}
     * @default 0
     */
    maxRows: {
      type: Number,
      value: 0,
    },
  },

  /**
   * @return {number}
   */
  get selectionStart() {
    return this.$.input.textarea.selectionStart;
  },

  set selectionStart(start) {
    this.$.input.textarea.selectionStart = start;
  },

  /**
   * @return {number}
   */
  get selectionEnd() {
    return this.$.input.textarea.selectionEnd;
  },

  set selectionEnd(end) {
    this.$.input.textarea.selectionEnd = end;
  },

  _ariaLabelledByChanged: function(ariaLabelledBy) {
    this._focusableElement.setAttribute('aria-labelledby', ariaLabelledBy);
  },

  _ariaDescribedByChanged: function(ariaDescribedBy) {
    this._focusableElement.setAttribute('aria-describedby', ariaDescribedBy);
  },

  get _focusableElement() {
    return this.inputElement.textarea;
  }
});