Why is yield classed as an operator and not a statement?

Question

I was looking at the mdn javascript reference and noticed that yield is listed in the operators section. On the other hand return is listed as a statement. I also found yield has a operator precedence of 2.

What features of yield make it fall into the operator class rather than a statement? Why does return fall into statements rather than operators?

Answer 1

It is an operator because it can be used in an expression.

function* g() {
    value = 3;
    while (value !== 5) value = Math.floor(yield value + 1);
}

var gen = g();

console.log(gen.next().value);
console.log(gen.next(1.5).value);