Skip to content

noUndeclaredCustomProperties (HTML)

biome.json
{
"linter": {
"rules": {
"nursery": {
"noUndeclaredCustomProperties": "error"
}
}
}
}

Reports custom properties used with var() that have no visible declaration.

<div style="color: var(--text-color)"></div>
code-block.html:1:24 lint/nursery/noUndeclaredCustomProperties ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━

The custom property --text-color is not defined.

> 1 │ <div style="color: var(--text-color)"></div>
^^^^^^^^^^^^
2 │

An undeclared custom property can indicate a misspelled name or a missing declaration.

Define the custom property in an available stylesheet, rename it or remove it.

This rule belongs to the nursery group, which means it is not yet stable and may change in the future. Visit https://biomejs.dev/linter/#nursery for more information.

<div style="--text-color: blue; color: var(--text-color)"></div>