or(value) {
        this._prefixes += '(?:';
        this._suffixes = `)${this._suffixes}`;

        this.add(')|(?:');

        if (value) {
            this.then(value);
        }

        return this;
    }
Add alternative expressions
@param {(string|RegExp|number)} value value to find
@returns {VerbalExpression} recompiled instance of VerbalExpression
@memberof VerbalExpression