iron-input.html

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<link rel="import" href="../polymer/polymer.html">
<link rel="import" href="../iron-a11y-announcer/iron-a11y-announcer.html">
<link rel="import" href="../iron-validatable-behavior/iron-validatable-behavior.html">
<link rel="import" href="../iron-validatable-behavior/iron-validation-trigger-behavior.html">

<script>

/*
`<iron-input>` adds two-way binding and custom validators using `Polymer.IronValidatorBehavior`
to `<input>`.

### Two-way binding

By default you can only get notified of changes to an `input`'s `value` due to user input:

    <input value="{{myValue::input}}">

`iron-input` adds the `bind-value` property that mirrors the `value` property, and can be used
for two-way data binding. `bind-value` will notify if it is changed either by user input or by script.

    <input is="iron-input" bind-value="{{myValue}}">

### Custom validators

You can use custom validators that implement `Polymer.IronValidatorBehavior` with `<iron-input>`.

    <input is="iron-input" validator="my-custom-validator">

### Stopping invalid input

It may be desirable to only allow users to enter certain characters. You can use the
`prevent-invalid-input` and `allowed-pattern` attributes together to accomplish this. This feature
is separate from validation, and `allowed-pattern` does not affect how the input is validated.

    <!-- only allow characters that match [0-9] -->
    <input is="iron-input" prevent-invalid-input allowed-pattern="[0-9]">

@hero hero.svg
@demo demo/index.html
*/

  Polymer({

    is: 'iron-input',

    extends: 'input',

    behaviors: [
      Polymer.IronValidatableBehavior,
      Polymer.IronValidationTriggerBehavior
    ],

    properties: {

      /**
       * Use this property instead of `value` for two-way data binding.
       */
      bindValue: {
        observer: '_bindValueChanged',
        type: String
      },

      /**
       * Set to true to prevent the user from entering invalid input. If `allowedPattern` is set,
       * any character typed by the user will be matched against that pattern, and rejected if it's not a match.
       * Pasted input will have each character checked individually; if any character
       * doesn't match `allowedPattern`, the entire pasted string will be rejected.
       * If `allowedPattern` is not set, it will use the `type` attribute (only supported for `type=number`).
       */
      preventInvalidInput: {
        type: Boolean
      },

      /**
       * Regular expression that list the characters allowed as input.
       * This pattern represents the allowed characters for the field; as the user inputs text,
       * each individual character will be checked against the pattern (rather than checking
       * the entire value as a whole). The recommended format should be a list of allowed characters;
       * for example, `[a-zA-Z0-9.+-!;:]`
       */
      allowedPattern: {
        type: String,
        observer: "_allowedPatternChanged"
      },

      _previousValidInput: {
        type: String,
        value: ''
      },

      _patternAlreadyChecked: {
        type: Boolean,
        value: false
      }

    },

    listeners: {
      'input': '_onInput',
      'keypress': '_onKeypress'
    },

    registered: function() {
      // Feature detect whether we need to patch dispatchEvent (i.e. on FF and IE).
      if (!this._canDispatchEventOnDisabled()) {
        this._origDispatchEvent = this.dispatchEvent;
        this.dispatchEvent = this._dispatchEventFirefoxIE;
      }
    },

    created: function() {
      Polymer.IronA11yAnnouncer.requestAvailability();
    },

    _canDispatchEventOnDisabled: function() {
      var input = document.createElement('input');
      var canDispatch = false;
      input.disabled = true;

      input.addEventListener('feature-check-dispatch-event', function() {
        canDispatch = true;
      });

      try {
        input.dispatchEvent(new Event('feature-check-dispatch-event'));
      } catch(e) {}

      return canDispatch;
    },

    /**
     * @this {Node}
     * @param {!Event} event
     * @return {boolean}
     */
    _dispatchEventFirefoxIE: function(event) {
      // Due to Firefox bug, events fired on disabled form controls can throw
      // errors; furthermore, neither IE nor Firefox will actually dispatch
      // events from disabled form controls; as such, we toggle disable around
      // the dispatch to allow notifying properties to notify
      // See issue #47 for details
      var disabled = this.disabled;
      this.disabled = false;
      var defaultPrevented = this._origDispatchEvent(event);
      this.disabled = disabled;
      return defaultPrevented
    },

    get _patternRegExp() {
      var pattern;
      if (this.allowedPattern) {
        pattern = new RegExp(this.allowedPattern);
      } else {
        switch (this.type) {
          case 'number':
            pattern = /[0-9.,e-]/;
            break;
        }
      }
      return pattern;
    },

    ready: function() {
      this.bindValue = this.value;
    },

    /**
     * @suppress {checkTypes}
     */
    _bindValueChanged: function() {
      if (this.value !== this.bindValue) {
        this.value = !(this.bindValue || this.bindValue === 0 || this.bindValue === false) ? '' : this.bindValue;
      }
      // manually notify because we don't want to notify until after setting value
      this.fire('bind-value-changed', {value: this.bindValue});
    },

    _allowedPatternChanged: function() {
      // Force to prevent invalid input when an `allowed-pattern` is set
      this.preventInvalidInput = this.allowedPattern ? true : false;
    },

    _onInput: function() {
      // Need to validate each of the characters pasted if they haven't
      // been validated inside `_onKeypress` already.
      if (this.preventInvalidInput && !this._patternAlreadyChecked) {
        var valid = this._checkPatternValidity();
        if (!valid) {
          this._announceInvalidCharacter('Invalid string of characters not entered.');
          this.value = this._previousValidInput;
        }
      }

      this.bindValue = this.value;
      this._previousValidInput = this.value;
      this._patternAlreadyChecked = false;
    },

    _isPrintable: function(event) {
      // What a control/printable character is varies wildly based on the browser.
      // - most control characters (arrows, backspace) do not send a `keypress` event
      //   in Chrome, but the *do* on Firefox
      // - in Firefox, when they do send a `keypress` event, control chars have
      //   a charCode = 0, keyCode = xx (for ex. 40 for down arrow)
      // - printable characters always send a keypress event.
      // - in Firefox, printable chars always have a keyCode = 0. In Chrome, the keyCode
      //   always matches the charCode.
      // None of this makes any sense.

      // For these keys, ASCII code == browser keycode.
      var anyNonPrintable =
        (event.keyCode == 8)   ||  // backspace
        (event.keyCode == 9)   ||  // tab
        (event.keyCode == 13)  ||  // enter
        (event.keyCode == 27);     // escape

      // For these keys, make sure it's a browser keycode and not an ASCII code.
      var mozNonPrintable =
        (event.keyCode == 19)  ||  // pause
        (event.keyCode == 20)  ||  // caps lock
        (event.keyCode == 45)  ||  // insert
        (event.keyCode == 46)  ||  // delete
        (event.keyCode == 144) ||  // num lock
        (event.keyCode == 145) ||  // scroll lock
        (event.keyCode > 32 && event.keyCode < 41)   || // page up/down, end, home, arrows
        (event.keyCode > 111 && event.keyCode < 124); // fn keys

      return !anyNonPrintable && !(event.charCode == 0 && mozNonPrintable);
    },

    _onKeypress: function(event) {
      if (!this.preventInvalidInput && this.type !== 'number') {
        return;
      }
      var regexp = this._patternRegExp;
      if (!regexp) {
        return;
      }

      // Handle special keys and backspace
      if (event.metaKey || event.ctrlKey || event.altKey)
        return;

      // Check the pattern either here or in `_onInput`, but not in both.
      this._patternAlreadyChecked = true;

      var thisChar = String.fromCharCode(event.charCode);
      if (this._isPrintable(event) && !regexp.test(thisChar)) {
        event.preventDefault();
        this._announceInvalidCharacter('Invalid character ' + thisChar + ' not entered.');
      }
    },

    _checkPatternValidity: function() {
      var regexp = this._patternRegExp;
      if (!regexp) {
        return true;
      }
      for (var i = 0; i < this.value.length; i++) {
        if (!regexp.test(this.value[i])) {
          return false;
        }
      }
      return true;
    },

    /**
     * Returns true if `value` is valid. The validator provided in `validator` will be used first,
     * then any constraints.
     * @return {boolean} True if the value is valid.
     */
    validate: function() {
      // Validatable is called first, so it will keep track of all individual states of validators that can be applied to it.
      var validatableOutcome = Polymer.IronValidatableBehavior.validate.call(this, this.value);

      var requiredValid = this.required ? this.value !== '' : true;
      var valid = validatableOutcome && this.checkValidity() && requiredValid;

      this.invalid = !valid;
      this.fire('iron-input-validate');
      return valid;
    },

    _announceInvalidCharacter: function(message) {
      this.fire('iron-announce', { text: message });
    }
  });

  /*
  The `iron-input-validate` event is fired whenever `validate()` is called.
  @event iron-input-validate
  */

</script>