no-duplicate-theme-config-metadata-keys

Disallow duplicate themeConfig.metadata keys across static name and property entries.

Targeted pattern scope

This rule targets docusaurus.config.* files and inspects themeConfig.metadata arrays.

What this rule reports

This rule reports duplicate metadata entries that repeat an earlier static name or property key.

Why this rule exists

Duplicate metadata keys make site metadata harder to audit and can produce redundant or conflicting document head output.

❌ Incorrect

export default {
    themeConfig: {
        metadata: [
            { name: "keywords", content: "docs" },
            { name: "keywords", content: "rules" },
        ],
    },
};

✅ Correct

export default {
    themeConfig: {
        metadata: [
            { name: "keywords", content: "docs, rules" },
        ],
    },
};

Behavior and migration notes

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

When not to use it

Do not use this rule if duplicate metadata keys are intentionally emitted and resolved by downstream rendering logic.

Rule catalog ID: R059

Targeted pattern scope​

What this rule reports​

Why this rule exists​

❌ Incorrect​

✅ Correct​

Behavior and migration notes​

When not to use it​

Further reading​