no-duplicate-head-tags

Disallow duplicate top-level headTags entries in Docusaurus config.

Targeted pattern scope

This rule targets docusaurus.config.* files and inspects the top-level headTags array.

What this rule reports

This rule reports later headTags object entries that repeat an earlier tag definition with the same serialized signature.

Why this rule exists

Duplicate head tags create noisy document metadata, repeated preload/preconnect hints, and harder-to-review config.

❌ Incorrect

export default {
    headTags: [
        {
            tagName: "link",
            attributes: { rel: "preconnect", href: "https://github.com" },
        },
        {
            tagName: "link",
            attributes: { rel: "preconnect", href: "https://github.com" },
        },
    ],
};

✅ Correct

export default {
    headTags: [
        {
            tagName: "link",
            attributes: { rel: "preconnect", href: "https://github.com" },
        },
    ],
};

Behavior and migration notes

This rule autofixes by removing later duplicate headTags entries after the first occurrence.

When not to use it

Do not use this rule if duplicate top-level head tags are intentionally emitted for downstream processing.

Rule catalog ID: R061

Further reading

• Docusaurus site config reference