The function reduces the countObjVals array to a single object reducedValue that contains the count and the qty fields. Integration. The interface type that specifies zero methods is known as the empty interface: interface{} An empty interface may hold values of any type. For checking the emptiness of an array we will use array.length. BinaryOperator = functional interface, take two values and produces a new value. Its syntax is as follows − array.reduce(callback[, initialValue]); Parameter Details. Initialization: Given no initial accumulator value, a transducer must call the step function to produce a valid initial value to act on. link brightness_4 code