Question

我正在构建一个角度节点应用评级系统。在该系统中，我试图循环遍历作为POST请求发送到服务器的id数组，并使用for循环将这些id推送到用户需要对列进行评级。

第一个用户成功获取整个循环，但下一个用户在第二个索引处失败。经过调试，我发现后端正在接收所有正确的变量，我不明白为什么它不适用于用户2而是用于用户。

这是我的后端代码

 addRatee: function addRatee(req,res) {
    var decoded = jwt.decode(req.query.token);
    return model.User.findById(req.params.raterId)
      .then(function (user) {
      for (let ratee of req.body.rateeIds) {
        user.needToRate.push(ratee);
      }
      user.update({
        needToRate: user.needToRate
      }).then(function (updatedUser) {
        return res.status(200).json({
          title: "Successfully added users to need to rate",
          obj: updatedUser
        });
      }).catch(function () {
        return res.status(400).json({
          message: "Error updating user",
          error: err.toString()
        });
      });
    }).catch(function (e) {
      return res.status(400).json({
        message: "Error finding user",
        error: e.toString()
      });
    });
  }

这是我的组件服务代码

 addRatee(rateeIds: number[], raterId: number) {
    const headers = new Headers({'Content-Type': 'application/json'});
    const token = localStorage.getItem('token')
      ? '?token=' + localStorage.getItem('token')
      : '';
    const body = {
      rateeIds: rateeIds
    };
    return this.http.patch(this.devUrl + '/new-ratee/' + raterId + token, body, {headers: headers});
  }

这是我的component.ts代码

let dRateeIds = [this.trip.rider1Id, this.trip.rider2Id, this.trip.rider3Id];
              let r1RateeIds = [this.trip.driverId, this.trip.rider2Id, this.trip.rider3Id];
              let r2RateeIds = [this.trip.rider1Id, this.trip.driverId, this.trip.rider3Id];
              let r3RateeIds = [this.trip.rider1Id, this.trip.rider2Id, this.trip.driverId];
                  this.tripService.addRatee(dRateeIds, this.trip.driverId)
                    .subscribe(updatedUser => {
                      console.log(updatedUser);
                      this.tripService.addRatee(r1RateeIds, this.trip.rider1Id)
                        .subscribe(updatedUser2 => {
                          console.log(updatedUser2);
                      this.tripService.addRatee(r2RateeIds, this.trip.rider2Id)
                        .subscribe(updatedUser3 => {
                          console.log(updatedUser3);
                          this.tripService.addRatee(r3RateeIds, this.trip.rider3Id)
                            .subscribe(updatedUser4 => {
                              console.log(updatedUser4);
                            }, resp => console.log(resp));
                        }, resp => console.log(resp));
                    }, resp => console.log(resp));
                }, resp => console.log(resp));

我对编程很新，所以我的代码有点混乱，我只是在寻找发生此错误的原因。

这是给出的完整错误堆栈。

{"message":"Error finding user","error":"TypeError: Cannot read property 'push' of null\n    at /Users/jonathancorrin/Desktop/workspace/atlas-web/server/controllers/trips.js:1380:24\n    at tryCatcher (/Users/jonathancorrin/Desktop/workspace/atlas-web/node_modules/bluebird/js/release/util.js:16:23)\n    at Promise._settlePromiseFromHandler (/Users/jonathancorrin/Desktop/workspace/atlas-web/node_modules/bluebird/js/release/promise.js:512:31)\n    at Promise._settlePromise (/Users/jonathancorrin/Desktop/workspace/atlas-web/node_modules/bluebird/js/release/promise.js:569:18)\n    at Promise._settlePromise0 (/Users/jonathancorrin/Desktop/workspace/atlas-web/node_modules/bluebird/js/release/promise.js:614:10)\n    at Promise._settlePromises (/Users/jonathancorrin/Desktop/workspace/atlas-web/node_modules/bluebird/js/release/promise.js:693:18)\n    at Async._drainQueue (/Users/jonathancorrin/Desktop/workspace/atlas-web/node_modules/bluebird/js/release/async.js:133:16)\n    at Async._drainQueues (/Users/jonathancorrin/Desktop/workspace/atlas-web/node_modules/bluebird/js/release/async.js:143:10)\n    at Immediate.Async.drainQueues (/Users/jonathancorrin/Desktop/workspace/atlas-web/node_modules/bluebird/js/release/async.js:17:14)\n    at runCallback (timers.js:781:20)\n    at tryOnImmediate (timers.js:743:5)\n    at processImmediate [as _immediateCallback] (timers.js:714:5)"}

这是我的pgadmin表在几次尝试失败后的样子。空值为用户2-4

******更新以下是在配置之前记录needsToRate列和值类型

时记录的值

用户需要评估====== null USER TYPE NTR ========== object

Answer 1

这个问题是我试图将值推送到空字段。我用这段代码解决了这个问题

 for (let ratee of req.body.rateeIds) {
        if (user.needToRate === null) {
          user.needToRate = [];
          user.needToRate.push(ratee)
        } else {
          user.needToRate.push(ratee)
        }
      }

“TypeError：无法读取多个请求的属性'push'of null”

1 个答案: