list_length

Checks the number of items in a list.

Error codes: TOO_FEW_ITEMS, TOO_MANY_ITEMS, FORMAT_ERROR

Live example · edit rules or inputOpen in playground

rules

{
    tags: { list_length: [1, 3] }
}

{
    tags: { list_length: [1, 3] }
}

input

{
    tags: ['a', 'b', 'c', 'd']
}

{
    tags: ['a', 'b', 'c', 'd']
}

Invaliderrors

{
  "tags": "TOO_MANY_ITEMS"
}

The arguments are a non-negative integer (the exact length), two non-negative integers min, max, or an object with min, max or both:

{ tags:   { list_length: [1, 10] } }
{ pair:   { list_length: 2 } }
{ items:  { list_length: { max: 100 } } }
{ photos: { list_length: { min: 1 } } }

The first argument and the count select the form: an object first is the options form, otherwise two or more arguments are min, max, and one is the exact length. So { list_length: [3, 'x'] } is a schema error, not an exact length of 3.

The value must be a list, otherwise FORMAT_ERROR.
Too few items give TOO_FEW_ITEMS, too many give TOO_MANY_ITEMS.
An empty list [] is a value, not an empty value: { list_length: { min: 1 } } rejects it.
The output is the value unchanged.

list_length ​

list_length