generator-throw.js

function* g() {
  try {
    yield 1 // throws 'first error'
  } catch (error) { // catches 'first error'
    console.error('inside generator', error)
  }
  yield 2 // throws but does not catch 'second error'
  return 3 // never reached because exception thrown
}

const generator = g()
generator.next() // { value: 1, done: false }
generator.throw('first error') // { value: 2, done: false }
try {
  generator.throw('second error') // exception escapes generator
} catch (error) { // catches 'second error'
  console.error('outside generator', error)
}
generator.next() // { value: undefined, done: true }