Headers.forEach()

The Headers.forEach() method executes a callback function once per each key/value pair in the Headers object.

The Headers.forEach() method executes the provided callback once for each key of the Headers which actually exist. It is not invoked for keys which have been deleted. However, it is executed for keys which are present but have the value undefined.

Inputs: callbackFn Function to execute for each entry in the map. It takes the following arguments: value Value of the currently visited header entry. key Name of the currently visited header entry. object The Headers object being iterated. thisArg Value to use as this when executing callback.