---
url: /reference/@cssdoc/providers/functions/checkPropertyUsage.md
---
# Function: checkPropertyUsage()

```ts
function checkPropertyUsage(
   usages, 
   index, 
   options?, 
   severities?
): Diagnostic[];
```

Defined in: [packages/providers/src/index.ts:144](https://github.com/thedannywahl/cssdoc/blob/main/packages/providers/src/index.ts#L144)

Consumer-side diagnostics for `var(--…)` references (unknown custom properties; opt-in via prefix).

## Parameters

### usages

readonly [`PropertyUsage`](../../index/interfaces/PropertyUsage.md)\[]

### index

[`CssDocIndex`](../../index/classes/CssDocIndex.md)

### options?

[`UsageOptions`](../../cssdoc/interfaces/UsageOptions.md) = `{}`

### severities?

[`RuleSeverities`](../../cssdoc/type-aliases/RuleSeverities.md) = `DEFAULT_RULE_SEVERITIES`

## Returns

[`Diagnostic`](../../cssdoc/interfaces/Diagnostic.md)\[]