v2_question

const data = [{
  from:'a',to: 'e' 
},{
  from:'b',to: 'c'
},{
  from:'b',to: 'h'
},{
  from:'b',to: 'x'
},{
  from: 'c',to: 'e'
},{
  from: 'd',to: 'e'
},{
  from: 'a',to: 'd'
},{
  from: 'a',to: 'h'
},{
  from: 'h',to: 'd'
}]

// 路径寻找，从data 数据中， 找到所有起始点root 到 目标target点的路径 
// a -> e 结果[[a,e],[a,b,c,e],[a,d,e],[a,h,d,e]]
function findPath(data, root, target) {
  let res = []
  let childRes = [];
  (function dsf(data, root, target, res, childRes) {
    childRes.push(root)
    const nextPath = data.filter(d => {
      if (d.from == root) {
        d.isVisit = true
      }
      return d.from == root
    }).map(item => item.to)

    if (!nextPath.length) {
      childRes.pop()
      return
    }
    const nextData = data.filter(d => !d.isVisit)
    for (let i = 0; i < nextPath.length; i++) {
      let to = nextPath[i]
      if (to == target) {
        childRes.push(to)
        res.push(JSON.parse(JSON.stringify(childRes)))
        childRes.pop()
      } else {
        dsf(nextData, to, target, res, childRes)
      }
    }
  })(data, root, target, res, childRes)
  return res
}
console.log(findPath(data, 'a', 'e'))