如何检查一个对象是否存在于另一个对象中？

Question

Using the following array with two objects that include another object inside I would like to know if there is a way to find which is the applicationID has applicantID equal with "5bd3480af09ddf0258c3a31d"

Array [
  Object {
    "__typename": "JobApplication",
    "_id": "5be097753397465946e051fd",
    "applicant": Object {
      "__typename": "User",
      "_id": "5bd83b9a62a9f33cf0f1033b",
    },
  },
  Object {
    "__typename": "JobApplication",
    "_id": "5bdc7c8b3241cb5bc10ac694",
    "applicant": Object {
      "__typename": "User",
      "_id": "5bd3480af09ddf0258c3a31d",
    },
  },
]

So in this case it has to return "5bdc7c8b3241cb5bc10ac694".

This are my two constants first will return the user id and second will return only the applications id.

const { _id } = this.props.getMe.me._id;
const applicationID = getJobApplicationsForThisJob.map(application => application._id);

I could check if the user id is in any of the objects like this

const applicantId = getJobApplicationsForThisJob.map(user => user.applicant._id);
const hasApplied = applicantId.includes(_id);

Thanks

Answer 1

You can use the .find method.

var item = arr.find(function(x) {
  return x.applicant._id == find;
});

The find method returns the first found item or undefined if a record was not found.

 var arr = [{ "__typename": "JobApplication", "_id": "5be097753397465946e051fd", "applicant": { "__typename": "User", "_id": "5bd83b9a62a9f33cf0f1033b", } }, { "__typename": "JobApplication", "_id": "5bdc7c8b3241cb5bc10ac694", "applicant": { "__typename": "User", "_id": "5bd3480af09ddf0258c3a31d", }, }]; var find = "5bd3480af09ddf0258c3a31d"; var item = arr.find(function(x) { return x.applicant._id == find; }); console.log(item != undefined ? item._id : "Not Found"); 

Answer 2

Since you are using Javascript, you would want to do something like my comment,

let _id = "5bd3480af09ddf0258c3a31d";
let list = [];  //your list of objects.
let applicationResults = list.where( (app) => app.applicant._id = _id);
if (applicationResults.length == 0){
  console.log("no applicantion with this applicant found.");
}else {
  console.log("Found " + applicationResults.length + " Applications from this Applicant")
  return applicationResults;
}