no-return-wrap.md

Pattern: Wrapping in Promise.resolve or Promise.reject

Issue: -

Description

Ensure that inside a then() or a catch() we always return or throw a raw value instead of wrapping in Promise.resolve or Promise.reject

Example of correct code:

myPromise.then(function(val) {
  return val * 2
})
myPromise.then(function(val) {
  throw 'bad thing'
})

Example of incorrect code:

myPromise.then(function(val) {
  return Promise.resolve(val * 2)
})
myPromise.then(function(val) {
  return Promise.reject('bad thing')
})

Options

allowReject

Pass { allowReject: true } as an option to this rule to permit wrapping returned values with Promise.reject, such as when you would use it as another way to reject the promise.

param-names

Enforce standard parameter names for Promise constructors

Example of correct code:

new Promise(function (resolve) { ... })
new Promise(function (resolve, reject) { ... })

Example of incorrect code:

new Promise(function (reject, resolve) { ... }) // incorrect order
new Promise(function (ok, fail) { ... }) // non-standard parameter names

Ensures that new Promise() is instantiated with the parameter names resolve, reject to avoid confusion with order such as reject, resolve. The Promise constructor uses the RevealingConstructor pattern. Using the same parameter names as the language specification makes code more uniform and easier to understand.

Further Reading

• eslint-plugin-promise - no-return-wrap