joplin/packages/lib/countable/Countable.js

// ========================================================================
// Imported from dead package https://github.com/RadLikeWhoa/Countable
//
// 2023-06-05: Added "—" as word separator.
// ========================================================================

/**
 * Countable is a script to allow for live paragraph-, word- and character-
 * counting on an HTML element.
 *
 * @author   Sacha Schmid (<https://github.com/RadLikeWhoa>)
 * @version  3.0.1
 * @license  MIT
 * @see      <http://radlikewhoa.github.io/Countable/>
 */

/**
 * Note: For the purpose of this internal documentation, arguments of the type
 * {Nodes} are to be interpreted as either {NodeList} or {Element}.
 */

;(function (global) {
	'use strict'
  
	/**
	 * @private
	 *
	 * `liveElements` holds all elements that have the live-counting
	 * functionality bound to them.
	 */
  
	let liveElements = []
	const each = Array.prototype.forEach
  
	/**
	 * `ucs2decode` function from the punycode.js library.
	 *
	 * Creates an array containing the decimal code points of each Unicode
	 * character in the string. While JavaScript uses UCS-2 internally, this
	 * function will convert a pair of surrogate halves (each of which UCS-2
	 * exposes as separate characters) into a single code point, matching
	 * UTF-16.
	 *
	 * @see     <http://goo.gl/8M09r>
	 * @see     <http://goo.gl/u4UUC>
	 *
	 * @param   {String}  string   The Unicode input string (UCS-2).
	 *
	 * @return  {Array}   The new array of code points.
	 */
  
	function decode (string) {
	  const output = []
		let counter = 0
		const length = string.length
  
		while (counter < length) {
			const value = string.charCodeAt(counter++)
  
			if (value >= 0xD800 && value <= 0xDBFF && counter < length) {
  
				// It's a high surrogate, and there is a next character.
  
				const extra = string.charCodeAt(counter++)
  
				if ((extra & 0xFC00) == 0xDC00) { // Low surrogate.
					output.push(((value & 0x3FF) << 10) + (extra & 0x3FF) + 0x10000)
				} else {
  
					// It's an unmatched surrogate; only append this code unit, in case the
					// next code unit is the high surrogate of a surrogate pair.
  
					output.push(value)
					counter--
				}
			} else {
				output.push(value)
			}
		}
  
		return output
	}
  
	/**
	 * `validateArguments` validates the arguments given to each function call.
	 * Errors are logged to the console as warnings, but Countable fails
	 * silently.
	 *
	 * @private
	 *
	 * @param   {Nodes|String}  targets   A (collection of) element(s) or a single
	   *                                    string to validate.
	 *
	 * @param   {Function}      callback  The callback function to validate.
	 *
	 * @return  {Boolean}       Returns whether all arguments are valid.
	 */
  
	function validateArguments (targets, callback) {
	  const nodes = Object.prototype.toString.call(targets)
	  const targetsValid = typeof targets === 'string' || ((nodes === '[object NodeList]' || nodes === '[object HTMLCollection]') || targets.nodeType === 1)
	  const callbackValid = typeof callback === 'function'
  
	  if (!targetsValid) console.error('Countable: Not a valid target')
	  if (!callbackValid) console.error('Countable: Not a valid callback function')
  
	  return targetsValid && callbackValid
	}
  
	/**
	 * `count` trims an element's value, optionally strips HTML tags and counts
	 * paragraphs, sentences, words, characters and characters plus spaces.
	 *
	 * @private
	 *
	 * @param   {Node|String}  target   The target for the count.
	 *
	 * @param   {Object}   	   options  The options to use for the counting.
	 *
	 * @return  {Object}       The object containing the number of paragraphs,
	 *                         sentences, words, characters and characters
	   *                         plus spaces.
	 */
  
	function count (target, options) {
	  let original = '' + (typeof target === 'string' ? target : ('value' in target ? target.value : target.textContent))
	  options = options || {}
  
	  /**
	   * The initial implementation to allow for HTML tags stripping was created
	   * @craniumslows while the current one was created by @Rob--W.
	   *
	   * @see <http://goo.gl/Exmlr>
	   * @see <http://goo.gl/gFQQh>
	   */
  
	  if (options.stripTags) original = original.replace(/<\/?[a-z][^>]*>/gi, '')
  
	  if (options.ignore) {
		  each.call(options.ignore, function (i) {
			  original = original.replace(i, '')
		  })
	  }
  
	  const trimmed = original.trim()
  
	  /**
	   * Most of the performance improvements are based on the works of @epmatsw.
	   *
	   * @see <http://goo.gl/SWOLB>
	   */
  
	  return {
		paragraphs: trimmed ? (trimmed.match(options.hardReturns ? /\n{2,}/g : /\n+/g) || []).length + 1 : 0,
		sentences: trimmed ? (trimmed.match(/[.?!…]+./g) || []).length + 1 : 0,
		words: trimmed ? (trimmed.replace(/['";:,.?¿\-!¡]+/g, '').match(/\S+/g) || []).length : 0,
		characters: trimmed ? decode(trimmed.replace(/\s/g, '')).length : 0,
		all: decode(original).length
	  }
	}
  
	/**
	 * This is the main object that will later be exposed to other scripts. It
	 * holds all the public methods that can be used to enable the Countable
	 * functionality.
	 *
	 * Some methods accept an optional options parameter. This includes the
	 * following options.
	 *
	 * {Boolean}      hardReturns  Use two returns to seperate a paragraph
	 *                             instead of one. (default: false)
	 * {Boolean}      stripTags    Strip HTML tags before counting the values.
	 *                             (default: false)
	 * {Array<Char>}  ignore       A list of characters that should be removed
	 *                             ignored when calculating the counters.
	 *                             (default: )
	 */
  
	const Countable = {
  
	  /**
	   * The `on` method binds the counting handler to all given elements. The
	   * event is either `oninput` or `onkeydown`, based on the capabilities of
	   * the browser.
	   *
	   * @param   {Nodes}     elements   All elements that should receive the
	   *                                 Countable functionality.
	   *
	   * @param   {Function}  callback   The callback to fire whenever the
	   *                                 element's value changes. The callback is
	   *                                 called with the relevant element bound
	   *                                 to `this` and the counted values as the
	   *                                 single parameter.
	   *
	   * @param   {Object}    [options]  An object to modify Countable's
	   *                                 behaviour.
	   *
	   * @return  {Object}    Returns the Countable object to allow for chaining.
	   */
  
	  on: function (elements, callback, options) {
		if (!validateArguments(elements, callback)) return
  
		if (!Array.isArray(elements)) {
			elements = [ elements ]
		}
  
		each.call(elements, function (e) {
			const handler = function () {
			  callback.call(e, count(e, options))
			}
  
			liveElements.push({ element: e, handler: handler })
  
			handler()
  
			e.addEventListener('input', handler)
		})
  
		return this
	  },
  
	  /**
	   * The `off` method removes the Countable functionality from all given
	   * elements.
	   *
	   * @param   {Nodes}   elements  All elements whose Countable functionality
	   *                              should be unbound.
	   *
	   * @return  {Object}  Returns the Countable object to allow for chaining.
	   */
  
	  off: function (elements) {
		if (!validateArguments(elements, function () {})) return
  
		if (!Array.isArray(elements)) {
			elements = [ elements ]
		}
  
		liveElements.filter(function (e) {
			return elements.indexOf(e.element) !== -1
		}).forEach(function (e) {
			e.element.removeEventListener('input', e.handler)
		})
  
		liveElements = liveElements.filter(function (e) {
			return elements.indexOf(e.element) === -1
		})
  
		return this
	  },
  
	  /**
	   * The `count` method works mostly like the `live` method, but no events are
	   * bound, the functionality is only executed once.
	   *
	   * @param   {Nodes|String}  targets   All elements that should be counted.
	   *
	   * @param   {Function}      callback   The callback to fire whenever the
	   *                                     element's value changes. The callback
		   *                                     is called with the relevant element
		   *                                     bound to `this` and the counted values
		   *                                     as the single parameter.
	   *
	   * @param   {Object}        [options]  An object to modify Countable's
	   *                                     behaviour.
	   *
	   * @return  {Object}    Returns the Countable object to allow for chaining.
	   */
  
	  count: function (targets, callback, options) {
		if (!validateArguments(targets, callback)) return
  
		if (!Array.isArray(targets)) {
			targets = [ targets ]
		}
  
		each.call(targets, function (e) {
			callback.call(e, count(e, options))
		})
  
		return this
	  },
  
	  /**
	   * The `enabled` method checks if the live-counting functionality is bound
	   * to an element.
	   *
	   * @param   {Node}     element  All elements that should be checked for the
	   *                              Countable functionality.
	   *
	   * @return  {Boolean}  A boolean value representing whether Countable
	   *                     functionality is bound to all given elements.
	   */
  
	  enabled: function (elements) {
		if (elements.length === undefined) {
		  elements = [ elements ]
		}
  
		return liveElements.filter(function (e) {
			return elements.indexOf(e.element) !== -1
		}).length === elements.length
	  }
  
	}
  
	/**
	 * Expose Countable depending on the module system used across the
	 * application. (Node / CommonJS, AMD, global)
	 */
  
	if (typeof exports === 'object') {
	  module.exports = Countable
	} else if (typeof define === 'function' && define.amd) {
	  define(function () { return Countable })
	} else {
	  global.Countable = Countable
	}
  }(this));