valid-params.md

Enforces the proper number of arguments are passed to Promise functions (promise/valid-params)

⚠️ This rule warns in the following configs: ✅ flat/recommended, ✅ recommended.

Calling a Promise function with the incorrect number of arguments can lead to unexpected behavior or hard to spot bugs.

Rule Details

This rule is aimed at flagging instances where a Promise function is called with the improper number of arguments.

Examples of incorrect code for this rule:

• Promise.all() is called with 0 or 2+ arguments
• Promise.race() is called with 0 or 2+ arguments
• Promise.resolve() is called with 2+ arguments
• Promise.reject() is called with 2+ arguments
• Promise.then() is called with 0 or 3+ arguments
• Promise.catch() is called with 0 or 2+ arguments
• Promise.finally() is called with 0 or 2+ arguments

Examples of correct code for this rule:

// Promise.all() requires 1 argument
Promise.all([p1, p2, p3])
Promise.all(iterable)

// Promise.race() requires 1 argument
Promise.race([p1, p2, p3])
Promise.race(iterable)

// Promise.resolve() requires 0 or 1 arguments
Promise.resolve()
Promise.resolve({})
Promise.resolve([1, 2, 3])
Promise.resolve(referenceToObject)

// Promise.reject() requires 0 or 1 arguments
Promise.reject()
Promise.reject(Error())
Promise.reject(referenceToError)

// Promise.then() requires 1 or 2 arguments
somePromise().then((value) => doSomething(value))
somePromise().then(successCallback, errorCallback)

// Promise.catch() requires 1 argument
somePromise().catch((error) => {
  handleError(error)
})
somePromise().catch(console.error)

// Promise.finally() requires 1 argument
somePromise().finally(() => {
  console.log('done!')
})
somePromise().finally(console.log)

Options

exclude

Array of method names to exclude from checks. Defaults to an empty array.

When Not To Use It

If you do not want to be notified when passing an invalid number of arguments to a Promise function (for example, when using a typechecker like Flow), you can safely disable this rule.