label-has-for.md

label-has-for

Enforce label tags have associated control.

There are two supported ways to associate a label with a control:

• nesting: by wrapping a control in a label tag
• id: by using the prop htmlFor as in htmlFor=[ID of control]

To fully cover 100% of assistive devices, you're encouraged to validate for both nesting and id.

Rule details

This rule takes one optional object argument of type object:

{
    "rules": {
        "jsx-a11y/label-has-for": [ 2, {
            "components": [ "Label" ],
            "required": {
                "every": [ "nesting", "id" ]
            },
            "allowChildren": false
        }]
    }
}

For the components option, these strings determine which JSX elements (always including <label>) should be checked for having htmlFor prop. This is a good use case when you have a wrapper component that simply renders a label element (like in React):

// Label.js
const Label = props => {
  const {
    htmlFor,
    ...otherProps
  } = props;

  return (
    <label htmlFor={htmlFor} {...otherProps} />
  );
}

...

// CreateAccount.js (for example)
...
return (
  <form>
    <input id="firstName" type="text" />
    <Label htmlFor="firstName">First Name</Label>
  </form>
);

The required option (defaults to "required": { "every": ["nesting", "id"] }) determines which checks are activated. You're allowed to pass in one of the following types:

• string: must be one of the acceptable strings ("nesting" or "id")

• object, must have one of the following properties:

  • some: an array of acceptable strings, will pass if ANY of the requested checks passed
  • every: an array of acceptable strings, will pass if ALL of the requested checks passed

The allowChildren option (defaults to false) determines whether {children} content is allowed to be passed into a label element. For example, the following pattern, by default, is not allowed:

<label>{children}</label>

However, if allowChildren is set to true, no error will be raised. If you want to pass in {children} content without raising an error, because you cannot be sure what {children} will render, then set allowChildren to true.

Note that passing props as spread attribute without htmlFor explicitly defined will cause this rule to fail. Explicitly pass down htmlFor prop for rule to pass. The prop must have an actual value to pass. Use Label component above as a reference. It is a good thing to explicitly pass props that you expect to be passed for self-documentation. For example:

Bad

function Foo(props) {
  return <label {...props} />
}

Good

function Foo({ htmlFor, ...props}) {
    return <label htmlFor={htmlFor} {...props} />
}

// OR

function Foo(props) {
    const {
        htmlFor,
        ...otherProps
    } = props;

   return <label htmlFor={htmlFor} {...otherProps} />
}

Succeed

<label htmlFor="firstName">
  <input type="text" id="firstName" />
  First Name
</label>

Fail

<input type="text" id="firstName" />
<label>First Name</label>