consume string rule

consume.js

const consumeAListOfRules = (str, topLevel) => {
    let rules = [];
    while (str.consume()) {
        try {
            const rule = consumeStringRule(str, topLevel);
            if (rule) {
                reules.push(rule)
            }
        } catch (error) {
            return rules;
        }
    }
}
const consumeStringRule = (str, topLevel) => {
    switch (true) {
        case str.token instanceof WhitespaceToken:
            return;
        case (str.token instanceof CDOToken || str.token instanceof CDCToken) && topLevel === 'top-level':
            return;
        case str.token instanceof EOFToken:
            throw new Error('EOF found');
        case str.token instanceof AtKeywordToken:
            str.reconsume()
            return consumeAnAtRule(str);
        default:
            str.reconsume()
            return consumeAQualifiedRule(str);
    }
}