no-object-rest-spread.md

no-object-rest-spread

This prevents the use of Object Rest & Spread patterns, for example:

let { a, ...x } = obj

let other = { a: 1, ...x }

These will not be allowed because they are not supported in the following browsers:

• Edge < 79
• Safari < 11.1
• Firefox < 55
• Chrome < 60

What is the Fix?

If you want to use the Spread pattern in Object literals then it is safe to use Object.assign instead. The following lines are equivalent:

let other = { a: 1, ...x }

let other = Object.assign({ a: 1 }, x)

If you want to use the Rest pattern in Object Assignment, then the easiest way is to use Object.keys(x).reduce. The following two code samples are equivalent:

let { a, ...x } = obj

let a = obj.a, x = Object.keys(obj).reduce((x, key) => {
  if (key !== 'a') x[key] = obj[key]
  return x
}, {})

This could lead to a lot of repetitive code, so you could also lift this function into a helper:

const without = (source, ...excluded) => Object.keys(obj).reduce((acc, key) => {
  if (excluded.indexOf(key) === -1) acc[key] = obj[key]
  return acc
}, {})

let a = obj.a, x = without(obj, 'a')

You can also use Lodash's without method, or Ramda's omit.

This can be safely disabled if you intend to compile code with the @babel/plugin-proposal-object-rest-spread Babel plugin, or @babel/preset-env.