In JavaScript, Map coercion refers to the automatic conversion of an object or an iterable (such as an array) into a Map using the Map constructor. This coercion happens implicitly when an object or iterable with key-value pairs is provided as an argument to the Map constructor.

Example: Here, the array keyValuePairs contains nested arrays representing key-value pairs. When this array is passed as an argument to the Map constructor, it is coerced into a Map, and the resulting Map (myMap) contains the key-value pairs from the array.

Map(3) { 'key1' => 'value1', 'key2' => 'value2', 'key3' => 'value3' }