arrayReduce function
Implementation
String arrayReduce(List array, Function iteratee, String accumulator,
[bool initAccumulator = false]) {
int index = -1;
final length = array.length;
if (initAccumulator && length > 0) {
accumulator = array[++index];
}
while (++index < length) {
accumulator = iteratee(accumulator, array[index], index);
}
return accumulator;
}