Constructor.
Optionalvalues: Record<string, any>an object who's enumerable properties will be added to this map
Add a value.
This method will append values to existing keys.
the key to use
the value to add; if undefined nothing will be added
Remove all properties from this map.
this object
Test if there are any values associated with a key.
the key to test
true if there is at least one value associated with the key
Get the first avaialble value assocaited with a key.
the key of the value to get
the first available value associated with the key, or undefined if not available
Test if the map is empty.
true if there are no entries in this map
Get an array of all keys in this map.
array of keys in this map, or an empty array if the map is empty
Get the entire mapping as a single-valued Map instance.
This will return the first avaialble value for every key in the mapping.
a new Map instance
Set a value.
This method will replace any existing values with just value.
the key to use
the value to set; if undefined nothing will be added
this object
Set multiple values.
This method will replace any existing values with those provided on values.
an object who's enumerable properties will be added to this map
this object
Remove all values associated with a key.
the key of the values to remove
the removed values, or undefined if no values were present for the given key
Get the number of entries in this map.
the number of entries in the map
Get the values associated with a key.
the key of the values to get
the array of values associated with the key, or undefined if not available
A case-insensitive, case-preserving string key multi-value map object.
This map supports
nullvalues but ignores attempts to add keys withundefinedvalues.