Rule Proposal: Ensure prop.type is an Object

[richardtallent]

Please describe what the rule should do:

Ensure that the type key for a property is passed as an Object, not as a string.

What category of rule is this? (place an "X" next to just one item)

[ ] Enforces code style
[x] Warns about a potential error
[ ] Suggests an alternate way of doing something
[ ] Other (please specify:)

Provide 2-3 code examples that this rule will warn about:

props: {
	myFieldWithBadType: {
		type: "Object",
		default: function() {
			return {}
		},
	},
	myOtherFieldWithBadType: {
		type: "Number",
		default: 1,
	},
}

Why should this rule be included in ESLint (instead of a plugin)?

Passing a string to type rather than the name of the type results in a rather opaque error message from deep in the bowels of Vue, and it's an easy mistake to make.

[michalsnik]

This is an interesting proposal @richardtallent It might indeed be useful for newcomers that learn Vue 👍

[chrisvfritz]

I like this! Though note that constructors rather than objects should be allowed. It would go in essentials and a more complete list of situations to warn about might be:

import Foo from './foo'
const Bar = ''

// ...

props: {
  a: 'Object',
  b: { type: 'Number' },
  c: `String`,
  d: Foo + ''
  e: Bar,
  f: 1,
  g: true,
  h: { type: {} },
}