yoastseo-dep/src/languageProcessing/helpers/syllables/DeviationFragment.js

Yoast clientside page analysis

import { isUndefined, pick } from "lodash-es";

/**
 * Represents a partial deviation when counting syllables
 *
 * @param {Object} options Extra options about how to match this fragment.
 * @param {string} options.location The location in the word where this deviation can occur.
 * @param {string} options.word The actual string that should be counted differently.
 * @param {number} options.syllables The amount of syllables this fragment has.
 * @param {string[]} [options.notFollowedBy] A list of characters that this fragment shouldn't be followed with.
 * @param {string[]} [options.alsoFollowedBy] A list of characters that this fragment could be followed with.
 *
 * @constructor
 */
function DeviationFragment( options ) {
	this._location = options.location;
	this._fragment = options.word;
	this._syllables = options.syllables;
	this._regex = null;

	this._options = pick( options, [ "notFollowedBy", "alsoFollowedBy" ] );
}

/**
 * Creates a regex that matches this fragment inside a word.
 *
 * @returns {void}
 */
DeviationFragment.prototype.createRegex = function() {
	let regexString = "";
	const options = this._options;

	let fragment = this._fragment;

	if ( ! isUndefined( options.notFollowedBy ) ) {
		fragment += "(?![" + options.notFollowedBy.join( "" ) + "])";
	}

	if ( ! isUndefined( options.alsoFollowedBy ) ) {
		fragment += "[" + options.alsoFollowedBy.join( "" ) + "]?";
	}

	switch ( this._location ) {
		case "atBeginning":
			regexString = "^" + fragment;
			break;

		case "atEnd":
			regexString = fragment + "$";
			break;

		case "atBeginningOrEnd":
			regexString = "(^" + fragment + ")|(" + fragment + "$)";
			break;

		default:
			regexString = fragment;
			break;
	}

	this._regex = new RegExp( regexString );
};

/**
 * Returns the regex that matches this fragment inside a word.
 *
 * @returns {RegExp} The regexp that matches this fragment.
 */
DeviationFragment.prototype.getRegex = function() {
	if ( null === this._regex ) {
		this.createRegex();
	}

	return this._regex;
};

/**
 * Returns whether or not this fragment occurs in a word.
 *
 * @param {string} word The word to match the fragment in.
 * @returns {boolean} Whether or not this fragment occurs in a word.
 */
DeviationFragment.prototype.occursIn = function( word ) {
	const regex = this.getRegex();

	return regex.test( word );
};

/**
 * Removes this fragment from the given word.
 *
 * @param {string} word The word to remove this fragment from.
 * @returns {string} The modified word.
 */
DeviationFragment.prototype.removeFrom = function( word ) {
	// Replace by a space to keep the remaining parts separated.
	return word.replace( this._fragment, " " );
};

/**
 * Returns the amount of syllables for this fragment.
 *
 * @returns {number} The amount of syllables for this fragment.
 */
DeviationFragment.prototype.getSyllables = function() {
	return this._syllables;
};

export default DeviationFragment;