Comparing results from two API calls and returning their difference in MEAN app

问题

EDIT: Since I wasn't able to find a correct solution, I changed the application's structure a bit and posted another question: Mongoose - find documents not in a list

I have a MEAN app with three models: User, Task, and for keeping track of which task is assigned to which user I have UserTask, which looks like this:

const mongoose = require("mongoose");
const autopopulate = require("mongoose-autopopulate");

const UserTaskSchema = mongoose.Schema({
  completed: { type: Boolean, default: false },
  userId: {
    type: mongoose.Schema.Types.ObjectId,
    ref: "User",
    autopopulate: true
  },
  taskId: {
    type: mongoose.Schema.Types.ObjectId,
    ref: "Task",
    autopopulate: true
  }      
});
UserTaskSchema.plugin(autopopulate);

module.exports = mongoose.model("UserTask", UserTaskSchema);

In my frontend app I have AngularJS services and I already have functions for getting all users, all tasks, and tasks which are assigned to a particular user (by getting all UserTasks with given userId. For example:

// user-task.service.js
function getAllUserTasksForUser(userId) {
  return $http
    .get("http://localhost:3333/userTasks/byUserId/" + userId)
    .then(function(response) {
      return response.data;
    });
}

// task-service.js
function getAllTasks() {
  return $http.get("http://localhost:3333/tasks").then(function(response) {
    return response.data;
  });
}

Then I'm using this data in my controllers like this:

userTaskService
    .getAllUserTasksForUser($routeParams.id)
    .then(data => (vm.userTasks = data));

...and because of autopopulate plugin I have complete User and Task objects inside the UserTasks that I get. So far, so good.

Now I need to get all Tasks which are not assigned to a particular User. I guess I should first get all Tasks, then all UserTasks for a given userId, and then make some kind of difference, with some "where-not-in" kind of filter.

I'm still a newbie for all the MEAN components, I'm not familiar with all those then()s and promises and stuff... and I'm really not sure how to do this. I tried using multiple then()s but with no success. Can anyone give me a hint?

回答1:

You can do at server/API side that will more efficient.

In client side, if you want to do then try below

var userid = $routeParams.id;
userTaskService
    .getAllTasks()
    .then((data) => {
        vm.userTasks = data.filter(task => task.userId !== userid)
    });

来源：https://stackoverflow.com/questions/51416648/comparing-results-from-two-api-calls-and-returning-their-difference-in-mean-app

标签

angularjs

mongoose

mean