1. function fn1 () {
    2. console.log(111)
    3. fn2()
    4. console.log('fn1')
    5. }
    6. function fn2 () {
    7. console.log(222)
    8. fn3()
    9. console.log('fn2')
    10. }
    11. function fn3 () {
    12. console.log(333)
    13. fn4()
    14. console.log('fn3')
    15. }
    16. function fn4 () {
    17. console.log(444)
    18. console.log('fn4')
    19. }
    20. fn1()

    image.png