Problem
Write a function named json_filter that takes a JSON formatted string as a parameter. The parameter encodes an array of objects where each object in the array has "mass", "density", "temperature", and "velocity" as its keys and each key maps to a number. This function must return a JSON string encoding an array of objects. The objects in that array should be the objects from the input whose temperature key is associated with a value greater than 45.84. in javascript.