It is possible to send a value to the generator by passing it to the next() method.
function* summer() {
let sum = 0, value;
while (true) {
// receive sent value
value = yield;
if (value === null) break;
// aggregate values
sum += value;
}
return sum;
}
let generator = summer();
// proceed until the first "yield" expression, ignoring the "value" argument
generator.next();
// from this point on, the generator aggregates values until we send "null"
generator.next(1);
generator.next(10);
generator.next(100);
// close the generator and collect the result
let sum = generator.next(null).value; // 111