DIYgod/RSSHub · error · Error

Unknown nav: ${nav}

Error message

Unknown nav: ${nav}

What it means

Thrown by the Douban channel subject route when the `nav` path parameter is not one of the four supported values ('0' through '3', mapping to 电影/电视剧/书籍/唱片). The route uses a switch statement with string literal cases; any other value falls through to the default case which throws a plain Error (not InvalidParameterError).

Source

Thrown at lib/routes/douban/channel/subject.ts:64

    const channel_name = channel_info_response.data.title;
    const data = response.data.modules[nav].payload.subjects;
    let nav_name: string;

    switch (nav) {
        case '0':
            nav_name = '电影';
            break;
        case '1':
            nav_name = '电视剧';
            break;
        case '2':
            nav_name = '书籍';
            break;
        case '3':
            nav_name = '唱片';
            break;
        default:
            throw new Error(`Unknown nav: ${nav}`);
    }

    return {
        title: `豆瓣${channel_name}频道-${nav_name}推荐`,
        link,
        description: `豆瓣${channel_name}频道书影音下的${nav_name}推荐`,

        item: data.map(({ title, extra, cover_img, url }) => {
            const rate = extra.rating_group.rating ? `${extra.rating_group.rating.value.toFixed(1)}分` : extra.rating_group.null_rating_reason;

            const description = `标题：${title} <br> 信息：${extra.short_info} <br> 评分：${rate} <br> <img src="${cover_img.url}">`;

            return {
                title,
                description,
                link: url,
            };
        }),

View on GitHub (pinned to bed535e087)

Solutions

1. Use only valid nav values: 0 (电影/Movie), 1 (电视剧/TV), 2 (书籍/Book), 3 (唱片/Music).
2. Check the route description table for the mapping.
3. Verify the nav value is a string '0'–'3', not a number or other format.

Example fix

// before
switch (nav) {
    case '0': ... break;
    // ...
    default: throw new Error(`Unknown nav: ${nav}`);
}

// after — use InvalidParameterError with valid options
const navMap: Record<string, string> = { '0': '电影', '1': '电视剧', '2': '书籍', '3': '唱片' };
const nav_name = navMap[nav];
if (!nav_name) {
    throw new InvalidParameterError(`Unknown nav: ${nav}. Valid values: 0, 1, 2, 3`);
}

const validNavValues = ['0', '1', '2', '3'];
function isValidDoubanNav(nav: string): boolean {
    return validNavValues.includes(nav);
}

if (!isValidDoubanNav(nav)) {
    throw new Error(`Invalid nav '${nav}'. Valid: 0 (Movie), 1 (TV), 2 (Book), 3 (Music)`);
}

function isDoubanNav(value: string): value is '0' | '1' | '2' | '3' {
    return ['0', '1', '2', '3'].includes(value);
}

try {
    const feed = await fetch(`${rsshubUrl}/douban/channel/${id}/subject/${nav}`);
} catch (e) {
    if (e.message.includes('Unknown nav')) {
        console.error(`Nav must be 0-3, got: ${nav}`);
    }
    throw e;
}

When it happens

Trigger: Calling /douban/channel/<id>/subject/<nav> where nav is 4, 5, 'movie', or any non-{0,1,2,3} value; passing a floating-point or padded number like '00' that doesn't match the string literal.

Common situations: Developer guesses the nav parameter instead of reading the route description table; a new subject category was added by Douban but not mapped in this route.

Related errors

• 不支持指定类型！
• 不支持指定类型！
• invalid type
• invalid type
• No topic named ${topic}

AI-assisted analysis of DIYgod/RSSHub@bed535e087 (2026-08-12). Data as JSON: /api/errors/3020d83367074dda. Report an issue: GitHub.