blockly/core/field_checkbox.js

/**
 * @license
 * Copyright 2012 Google LLC
 * SPDX-License-Identifier: Apache-2.0
 */

/**
 * @fileoverview Checkbox field.  Checked or not checked.
 * @author fraser@google.com (Neil Fraser)
 */
'use strict';

goog.provide('Blockly.FieldCheckbox');

/** @suppress {extraRequire} */
goog.require('Blockly.Events.BlockChange');
goog.require('Blockly.Field');
goog.require('Blockly.fieldRegistry');
goog.require('Blockly.utils.dom');
goog.require('Blockly.utils.object');


/**
 * Class for a checkbox field.
 * @param {string|boolean=} opt_value The initial value of the field. Should
 *    either be 'TRUE', 'FALSE' or a boolean. Defaults to 'FALSE'.
 * @param {Function=} opt_validator  A function that is called to validate
 *    changes to the field's value. Takes in a value ('TRUE' or 'FALSE') &
 *    returns a validated value ('TRUE' or 'FALSE'), or null to abort the
 *    change.
 * @param {Object=} opt_config A map of options used to configure the field.
 *    See the [field creation documentation]{@link https://developers.google.com/blockly/guides/create-custom-blocks/fields/built-in-fields/checkbox#creation}
 *    for a list of properties this parameter supports.
 * @extends {Blockly.Field}
 * @constructor
 */
Blockly.FieldCheckbox = function(opt_value, opt_validator, opt_config) {
  /**
   * Character for the check mark. Used to apply a different check mark
   * character to individual fields.
   * @type {?string}
   * @private
   */
  this.checkChar_ = null;

  Blockly.FieldCheckbox.superClass_.constructor.call(
      this, opt_value, opt_validator, opt_config);
};
Blockly.utils.object.inherits(Blockly.FieldCheckbox, Blockly.Field);

/**
 * The default value for this field.
 * @type {*}
 * @protected
 */
Blockly.FieldCheckbox.prototype.DEFAULT_VALUE = false;

/**
 * Construct a FieldCheckbox from a JSON arg object.
 * @param {!Object} options A JSON object with options (checked).
 * @return {!Blockly.FieldCheckbox} The new field instance.
 * @package
 * @nocollapse
 */
Blockly.FieldCheckbox.fromJson = function(options) {
  return new Blockly.FieldCheckbox(options['checked'], undefined, options);
};

/**
 * Default character for the checkmark.
 * @type {string}
 * @const
 */
Blockly.FieldCheckbox.CHECK_CHAR = '\u2713';

/**
 * Serializable fields are saved by the XML renderer, non-serializable fields
 * are not. Editable fields should also be serializable.
 * @type {boolean}
 */
Blockly.FieldCheckbox.prototype.SERIALIZABLE = true;

/**
 * Mouse cursor style when over the hotspot that initiates editability.
 */
Blockly.FieldCheckbox.prototype.CURSOR = 'default';

/**
 * Configure the field based on the given map of options.
 * @param {!Object} config A map of options to configure the field based on.
 * @protected
 * @override
 */
Blockly.FieldCheckbox.prototype.configure_ = function(config) {
  Blockly.FieldCheckbox.superClass_.configure_.call(this, config);
  if (config['checkCharacter']) {
    this.checkChar_ = config['checkCharacter'];
  }
};

/**
 * Create the block UI for this checkbox.
 * @package
 */
Blockly.FieldCheckbox.prototype.initView = function() {
  Blockly.FieldCheckbox.superClass_.initView.call(this);

  Blockly.utils.dom.addClass(
      /** @type {!SVGTextElement} **/ (this.textElement_), 'blocklyCheckbox');
  this.textElement_.style.display = this.value_ ? 'block' : 'none';
};

/**
 * @override
 */
Blockly.FieldCheckbox.prototype.render_ = function() {
  if (this.textContent_) {
    this.textContent_.nodeValue = this.getDisplayText_();
  }
  this.updateSize_(this.getConstants().FIELD_CHECKBOX_X_OFFSET);
};

/**
 * @override
 */
Blockly.FieldCheckbox.prototype.getDisplayText_ = function() {
  return this.checkChar_ || Blockly.FieldCheckbox.CHECK_CHAR;
};

/**
 * Set the character used for the check mark.
 * @param {?string} character The character to use for the check mark, or
 *    null to use the default.
 */
Blockly.FieldCheckbox.prototype.setCheckCharacter = function(character) {
  this.checkChar_ = character;
  this.forceRerender();
};

/**
 * Toggle the state of the checkbox on click.
 * @protected
 */
Blockly.FieldCheckbox.prototype.showEditor_ = function() {
  this.setValue(!this.value_);
};

/**
 * Ensure that the input value is valid ('TRUE' or 'FALSE').
 * @param {*=} opt_newValue The input value.
 * @return {?string} A valid value ('TRUE' or 'FALSE), or null if invalid.
 * @protected
 */
Blockly.FieldCheckbox.prototype.doClassValidation_ = function(opt_newValue) {
  if (opt_newValue === true || opt_newValue === 'TRUE') {
    return 'TRUE';
  }
  if (opt_newValue === false || opt_newValue === 'FALSE') {
    return 'FALSE';
  }
  return null;
};

/**
 * Update the value of the field, and update the checkElement.
 * @param {*} newValue The value to be saved. The default validator guarantees
 * that this is a either 'TRUE' or 'FALSE'.
 * @protected
 */
Blockly.FieldCheckbox.prototype.doValueUpdate_ = function(newValue) {
  this.value_ = this.convertValueToBool_(newValue);
  // Update visual.
  if (this.textElement_) {
    this.textElement_.style.display = this.value_ ? 'block' : 'none';
  }
};

/**
 * Get the value of this field, either 'TRUE' or 'FALSE'.
 * @return {string} The value of this field.
 */
Blockly.FieldCheckbox.prototype.getValue = function() {
  return this.value_ ? 'TRUE' : 'FALSE';
};

/**
 * Get the boolean value of this field.
 * @return {boolean} The boolean value of this field.
 */
Blockly.FieldCheckbox.prototype.getValueBoolean = function() {
  return /** @type {boolean} */ (this.value_);
};

/**
 * Get the text of this field. Used when the block is collapsed.
 * @return {string} Text representing the value of this field
 *    ('true' or 'false').
 */
Blockly.FieldCheckbox.prototype.getText = function() {
  return String(this.convertValueToBool_(this.value_));
};

/**
 * Convert a value into a pure boolean.
 *
 * Converts 'TRUE' to true and 'FALSE' to false correctly, everything else
 * is cast to a boolean.
 * @param {*} value The value to convert.
 * @return {boolean} The converted value.
 * @private
 */
Blockly.FieldCheckbox.prototype.convertValueToBool_ = function(value) {
  if (typeof value == 'string') {
    return value == 'TRUE';
  } else {
    return !!value;
  }
};

Blockly.fieldRegistry.register('field_checkbox', Blockly.FieldCheckbox);