Source: selector/methods/ClassSelector.js

(function() {
    const _prefix = ['help-id-'];

    /** @augments Help4.selector.methods.BaseSelector */
    Help4.selector.methods.ClassSelector = class extends Help4.selector.methods.BaseSelector {
        /**
         * @param {HTMLElement} element
         * @return {?Help4.selector.methods.Selector}
         */
        static getSelector(element) {
            const {methods, SELECTOR_QUALITY: {best: quality}} = Help4.selector;
            const {classList, nodeName} = element;

            for (const className of classList) {
                for (const prefix of _prefix) {
                    if (className.match(`^${prefix}`)) {
                        const value = nodeName + '.' + methods.$E(className);
                        if (methods.$(value).length === 1) return {value, quality};
                    }
                }
            }

            return null;
        }
    }
})();