Question

错误：

core.es5.js?0445:1084 ERROR SyntaxError: Unexpected token < in JSON at position 0
    at JSON.parse (<anonymous>

状况：

我想要达到的目的是预先选择用户之前已经做出的选择并阻止他投票两次。

CODE：

component.html

<article class="panel panel-default">
    <div class="panel-body">
      {{ poll.title }}
      <br>
      <br>
      <form #form="ngForm">
        <fieldset [disabled]="alreadyVotedFor(-1)">
          {{ poll.counter1 }} votes <input type="radio" id="{{ poll.choice1 }}" name="my_radio" value="{{ poll.choice1 }}" (click)="onChoice1(form)" [checked]="alreadyVotedFor(1)">  {{ poll.choice1 }}
          <br>
          {{ poll.counter2 }} votes <input type="radio" id="{{ poll.choice2  }}" name="my_radio" value="{{ poll.choice2 }}" (click)="onChoice2(form)" [checked]="alreadyVotedFor(2)">  {{ poll.choice2 }}
        </fieldset>
      </form>

    </div>
    <footer class="panel-footer">
        <div class="author">
            {{ poll.username }}
        </div>
        <div class="config" *ngIf="belongsToUser()">
            <a (click)="onEdit()">Edit</a>
            <a (click)="onDelete()">Delete</a>
        </div>
    </footer>
</article>

component.ts

votes: any;

    ngOnInit() {
        this.pollService.voted(this.poll, localStorage.getItem('userId')).subscribe(
            data => {
                this.votes = data.votes;
                console.log("NGONINIT this.votes: "+ this.votes);
            },
            err => { console.log("NGONINIT ERROR: "+ err) },
            () => { console.log("SUBSCRIBE COMPLETE this.votes: "+ this.votes); }
        );
    }

    alreadyVotedFor(choice: number) {
      let result = "";
      if (this.votes) {
          console.log("THIS.VOTES: "+this.votes);
          for (var i = 0; i < this.votes.length; i ++) {
              if (this.votes[i].poll == this.poll.pollId) {
                  result = "disabled";
                  if (this.votes[i].choice == choice) {
                      result =  "selected";
                  }
              }
          }
      }
      return result;
  }

服务

voted(poll: Poll, userID: string) {
    return this.http.get('http://localhost:3000/'+userID)
                    .map(response => response.json());
}

路由/ user.js的

router.get('/:userid', function (req, res, next) {
  var userId = req.params.userid;
  User.findById(userID, function (err, user) {
    console.log("USER JSON? :"+user.json());
    return res.send(user.json());
  });
});

模型/用户

var mongoose = require('mongoose');
var Schema = mongoose.Schema;
var mongooseUniqueValidator = require('mongoose-unique-validator');

var schema = new Schema({
    firstName: {type: String, required: true},
    lastName: {type: String, required: true},
    password: {type: String, required: true},
    email: {type: String, required: true, unique: true},
    polls: [{type: Schema.Types.ObjectId, ref: 'Poll'}],
    votes: [{
      poll: {type: Schema.Types.ObjectId, ref: 'Poll'},
      choice: {type: Number},
    }],
});

schema.plugin(mongooseUniqueValidator);

module.exports = mongoose.model('User', schema);

Answer 1

当服务器使用HTML而不是JSON响应时会发生此错误，尤其是在找不到路由且响应为404页时。

API不太可能是唯一一个以root身份挂载且可用http://localhost:3000/'+userID的路由，因为在这种情况下，服务器无法执行任何其他操作。< / p>

如果路线安装在某个路径上，例如

app.use('/user', userRoutes);

然后也应该对此路径执行请求

return this.http.get('http://localhost:3000/user/'+userID)

错误SyntaxError：意外的令牌＆lt;在位置0的JSON中

1 个答案: