js delete all array element if object contain something

Question

I got an array of objects Course.

export interface Course {
    id: string;
    student: User[];
    color: string;
}

export interface User {
    id: string;
    name: string;
    //...
}

I need to delete all element of the Course array, if the the student array inside him contain specific id

I was trying to do something like that but I don't understand what I'm suppose to do inside the filter part.

const deleteCourseWhereImIn = (courses: Course[]) => {
    const myid = "1111"
    return courses.filter((item):Course => 
        //[...]
    )
};

example:

the input:

const courses = [
    {
        id : "JSLKLDK",
        student: [
            {
                id: "1111",
                name: "John"
            },
            {
                id: "2222",
                name: "Ronald"
            },
            {
                id: "3333",
                name: "Tim"
            },
       ],
       color: "#f01000",
    },
    {
        id : "5JLDKLD",
        student: [
            {
                id: "2222",
                name: "Ronald"
            },
            {
                id: "1111",
                name: "John"
            },
       ],
       color: "#511131",
    },
    {
        id : "PDLFMLZ",
        student: [
            {
                id: "2222",
                name: "Ronald"
            },
       ],
       color: "#ffffff",
    },
]

my ID is 1111

the output should be:

const courses = [
    {
        id : "PDLFMLZ",
        student: [
            {
                id: "2222",
                name: "Ronald"
            },
       ],
       color: "#ffffff",
    },
]

because I'm john and I'm not in this course.

Brian Lee · Accepted Answer · 2020-11-12 12:21:50Z

Using filter and every:

const myID = "1111";

const courses = [
    {
        id : "JSLKLDK",
        student: [
            {
                id: "1111",
                name: "John"
            },
            {
                id: "2222",
                name: "Ronald"
            },
            {
                id: "3333",
                name: "Tim"
            },
       ],
       color: "#f01000",
    },
    {
        id : "5JLDKLD",
        student: [
            {
                id: "2222",
                name: "Ronald"
            },
            {
                id: "1111",
                name: "John"
            },
       ],
       color: "#511131",
    },
    {
        id : "PDLFMLZ",
        student: [
            {
                id: "2222",
                name: "Ronald"
            },
       ],
       color: "#ffffff",
    },
]

const filtered = courses.filter(c => c.student.every(s => s.id !== myID))

console.log(filtered);

user7847084 · Accepted Answer · 2020-11-12 12:23:50Z

1

Just use functional features of javascript.

const courses = [... your courses ...]
const idToCheck = "1111"
let newCourses = courses.filter(x => 
    x.student.findIndex(y => y.id == idToCheck) === -1)

answered Nov 12, 2020 at 12:23

user7847084

Comments

Abishek Kumar · Accepted Answer · 2020-11-12 12:22:08Z

1

Better use reduce to generate a new array and assign it to Course

let courses = [
    {
        id : "JSLKLDK",
        student: [
            {
                id: "1111",
                name: "John"
            },
            {
                id: "2222",
                name: "Ronald"
            },
            {
                id: "3333",
                name: "Tim"
            },
       ],
       color: "#f01000",
    },
    {
        id : "5JLDKLD",
        student: [
            {
                id: "2222",
                name: "Ronald"
            },
            {
                id: "1111",
                name: "John"
            },
       ],
       color: "#511131",
    },
    {
        id : "PDLFMLZ",
        student: [
            {
                id: "2222",
                name: "Ronald"
            },
       ],
       color: "#ffffff",
    },
]
courses = courses.reduce((arr, c)=>{
  if(!c.student.some((s)=>(s.id==='1111'))){
    arr.push(c);
  }
  return arr
},[])
console.log(courses);

edited Nov 12, 2020 at 12:22

answered Nov 12, 2020 at 12:19

Abishek Kumar

5395 silver badges15 bronze badges

5 Comments

Mitya Over a year ago

Please don't post just code in answers; it's far better to explain them, so the OP can learn something.

Abishek Kumar Over a year ago

I will update the answer, if you like you can suggest edit

Abishek Kumar Over a year ago

@Mitya thankx for the down vote I think I will stop answer questions all together in the future

Mitya Over a year ago

Don't take it so personally. Your answer had no explanation, and so was perfectly worthy of a downvote. You have now added some (admittedly minimal) explanation so I have retracted the downvote.

Mitya Over a year ago

Why are you asking me to edit? It's not for me to explain your answer for you, or for anyone else. You've done that now, the downvote is retracted, let's move on.

Lyubomir Vasilev · Accepted Answer · 2020-11-12 12:28:02Z

1

Using filter and findIndex:

const deleteCourseWhereImIn = (courses: Course[]) => {
    const myid = "1111";
    return courses.filter(item =>
        return item.student.findIndex(user => user.id == myid) === -1
    );
};

And here is a detailed version to better illustrate what is happening:

const deleteCourseWhereImIn = (courses: Course[]) => {
    const myid = "1111";

    const filteredCourses = courses.filter(item: Course => {
        const index = item.student.findIndex(user: User => {
             return user.id == myid
        });

        // The method findIndex() will return -1 if the value you search for does not appear in the array.
        return index === -1;
    });

    return filteredCourses;
};

edited Nov 12, 2020 at 12:28

answered Nov 12, 2020 at 12:22

Lyubomir Vasilev

3,04020 silver badges25 bronze badges

Comments

juanmajmjr · Accepted Answer · 2020-11-12 12:44:11Z

You can filter the courses with the condition id: "1111"by using filter and some. In your description you mention that you want to delete the courses that your are in.

For doing that, you can use this filter in your function deleteCourseWhereImIn and assign what it returns to your Course[].

let courses = [
    {
        id : "JSLKLDK",
        student: [
            {
                id: "1111",
                name: "John"
            },
            {
                id: "2222",
                name: "Ronald"
            },
            {
                id: "3333",
                name: "Tim"
            },
       ],
       color: "#f01000",
    },
    {
        id : "5JLDKLD",
        student: [
            {
                id: "2222",
                name: "Ronald"
            },
            {
                id: "1111",
                name: "John"
            },
       ],
       color: "#511131",
    },
    {
        id : "PDLFMLZ",
        student: [
            {
                id: "2222",
                name: "Ronald"
            },
       ],
       color: "#ffffff",
    },
]

courses = courses.filter(course => {
    return !course.student.some(student => student.id === "1111");
});


console.log(courses);

Sanu Kumar · Accepted Answer · 2020-11-12 13:51:00Z

Please try this.
I am passing the array of courses in the function deleteCourseWhereImIn() and then say myId is "1111". I am checking if any student in the student array has this id, and thus returning boolean value by using some() method. Then filter that particular course based on true or false.

    const deleteCourseWhereImIn = (courses: Course[]) => {
      const myId = "1111";
      let filteredCourses = courses.filter(course => {
        let studentArr = course.student;
        let filterdStudent = studentArr.some(student => student.id === myId);
        return !filterdStudent;
        
      });
    
      console.log('Filtered Course', filteredCourses);
    }
    
    deleteCourseWhereImIn(courses);  // calling function

Collectives™ on Stack Overflow

js delete all array element if object contain something

6 Answers 6

Comments

Comments

5 Comments

Comments

Comments

Comments

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

6 Answers 6

Comments

Comments

5 Comments

Comments

Comments

Comments

Your Answer

Sign up or log in

Post as a guest

Related