Function containsDuplicateValues

Returns true if array contains duplicate values.

containsDuplicateValues(['a','b','a']); // True
containsDuplicateValues([
 { name: 'Apple' },
 { name: 'Apple' }
]); // True

Uses JSON.toString() by default to compare values.

See also:

containsDuplicateInstances: Compare based on reference, rather than value
unique Get unique set of values in an array

containsDuplicateValues<V>(array, keyFunction?): boolean
Type Parameters
- V
Parameters
- array: V[] | readonly V[]
  Array to examine
- keyFunction: ((itemToMakeStringFor: V) => string) = ...
  Function to generate key string for object, uses JSON.stringify by default.
  - - (itemToMakeStringFor): string
    - A default converter to string that uses JSON.stringify if its an object, or the thing itself if it's a string
      
      Parameters
      itemToMakeStringFor: V
      Returns string
Returns boolean