Function hasCssVar

hasCssVar(
    name: `--${string}`,
    value?: CssVarValue,
    target?: null | Target,
): boolean
Checks if the target has the CSS variable with name. If a value is specified, checks that the values match.

If no target is specified, uses documentElement (i.e. :root).
Parameters
- name: `--${string}`
  Name of the CSS variable to check for.
- Optionalvalue: CssVarValue = undefined
  Optional value of the CSS variable to check for.
- Optionaltarget: null | Target = document.documentElement
  Optional Element, EventTarget, or CSS selector.
Returns boolean
true if the CSS variable name is present.
Throws
elements!InvalidElementError if the specified target wasn't found.
Example
HTML
```
<style>
  :root {
    --color-fg: green;
    --padding-small: "24px";
    --is-small: true;
  }
</style>

<button id="example" style="--color-bg: blue; --is-big: true;">
  Example
</button>
```
Check Element
```
const element = findElement("#example")!;

hasCssVar("--color-bg", undefined, element);
// true

hasCssVar("--is-big", "true", element);
// false ("true" cannot be a string, must be the boolean value `true`)

hasCssVar("--color-bg", "blue", element);
// true
```
Check :root
```
hasCssVar("--color-fg");
// true

hasCssVar("--is-small", "true");
// false ("true" cannot be a string, must be the boolean value `true`)

hasCssVar("--color-fg", "green");
// true
```
- Defined in src/css/hasCssVars.ts:80