javascript - 为什么我的递归函数似乎只运行一次？

Question

这是代码，它会遍历一个对象，寻找深度嵌套的子对象，并在没有更多子对象或超过 ALLOWED_NESTING_DEPTH 时停止。

console.log 似乎只运行一次，尽管我确实得到了正确的数字。

const ALLOWED_NESTING_DEPTH = 4

function traverseChildren (childrenIdList, parentsNesting = 0) {
  parentsNesting++

  if (parentsNesting > ALLOWED_NESTING_DEPTH || _.isEmpty(childrenIdList)) {
    console.log(parentsNesting) // Why does this show only once even if there are many levels of nesting?
    return parentsNesting
  }


  let children = childrenIdList.map(child => _.find(tree.items, { id: child }))
  let allChildren = []
  if (!_.isEmpty(children)) {
    allChildren = _.flattenDeep(children.map(child => child.children))
  }

  return traverseChildren(allChildren, parentsNesting)
}

traverseChildren(someChild)

Answer 1

当您进入此 block 时:

if (parentsNesting > ALLOWED_NESTING_DEPTH || _.isEmpty(childrenIdList)) {
    console.log(parentsNesting) // Why does this show only once even if there are many levels of nesting?
    return parentsNesting
  }

...您正在返回一个对象并且不再调用该函数。换句话说，这是您的终止案例。您只经过这里一次，因此您只会看到一个 console.log。