To pass JS Generator between functions like stream, you should not use `for (const v of gen)`

generator-test.ts

console.log('\nNG')
ng();
console.log('\nOK')
ok();

function ng() {
  let lex = gen(0, 10);
  for (const i of lex) {
    console.log(`top: ${i}`)
    if (i === 3) {
      scan1(lex)
    }
  }
}

function scan1(lex: Generator<number>) {
  for (const i of lex) {
    console.log(`scan1: ${i}`)
    if (i === 5) {
      scan2(lex)
    }
  }
}

function scan2(lex: Generator<number>) {
  for (const i of lex) {
    console.log(`scan2: ${i}`)
    if (i === 7)
      return;
  }
}

function ok() {
  let lex = gen(0, 10);
  let cur;
  while (!(cur = lex.next()).done) {
    const i = cur.value
    console.log(`top: ${i}`)
    if (i === 3) {
      ok_scan1(lex)
    }
  }
}

function ok_scan1(lex: Generator<number>) {
  let cur;
  while (!(cur = lex.next()).done) {
    const i = cur.value
    console.log(`scan1: ${i}`)
    if (i === 5) {
      ok_scan2(lex)
    }
  }
}

function ok_scan2(lex: Generator<number>) {
  let cur;
  while (!(cur = lex.next()).done) {
    const i = cur.value
    console.log(`scan2: ${i}`)
    if (i === 7)
      return;
  }
}

output.txt

NG
top: 0
top: 1
top: 2
top: 3
scan1: 4
scan1: 5
scan2: 6
scan2: 7

OK
top: 0
top: 1
top: 2
top: 3
scan1: 4
scan1: 5
scan2: 6
scan2: 7
scan1: 8
scan1: 9