how to remove an element from a list typescript

Question

Im using Angular 6, I have list and Im exporting it to CSV file using Angular5-csv, I want to remove the last column of the list i.e., the last element of each array in the list. my list looks like

let traceslist = [
{
  "name": "abcd",
  "email": "abcd@example.com",
  "decision": "yes",
  "userid": "abcd"
},
{
  "name": "phill";
  "email": "abcd@example.com";
  "decision": "yes";
  "userid": "phill";
},
{
  "name": "raj";
  "email": "raj@example.com";
  "decision": "no";
  "userid": "raj";
},
{
  "name": "john";
  "email": "john@example.com";
  "decision": "yes";
  "userid": "john";
}
]

now, I want to remove the elements userid, so that the column will not be present in my csv file, from the list. I have tried using splice but that was not successful.

It'd be great if anyone of you can help me with this.

Answer 1

You can't use delete to remove an item from an array. This is only used to remove a property from an object.

You should use splice to remove an element from an array:

deleteMsg(removeElement:string) {
    const index: number = traceslist.indexOf(removeElement);
    if (index !== -1) {
        traceslist.splice(index, 1);
    }        
}

Answer 2

First of all, your JSON format is wrong, semicolon (;) is first and the strings should be in quotes check it below

let obj = [{
    name: "abcd",
    email: "abcd@example.com",
    decision: "yes",
    userid: "abcd",

  },
  {
    name: "abcd",
    email: "abcd@example.com",
    decision: "yes",
    userid: "abcd",

  },
  {
    name: "raj",
    email: "raj@example.com",
    decision: "no",
    userid: "raj",

  },
  {
    name: "john",
    email: "john@example.com",
    decision: "yes",
    userid: "john",

  }
]

let filtered = obj.map(item => {
  delete item.userid;
  return item;
});
console.log(filtered);

Answer 3

We can use .map() method to achieve this

let traceslist = [
    {
        name: 'abcd',
        email: 'abcd@example.com',
        decision: 'yes',
        userid: 'abcd',
    },
    {
        name: 'abcd',
        email: 'abcd@example.com',
        decision: 'yes',
        userid: 'abcd',
    },
    {
        name: 'abcd',
        email: 'abcd@example.com',
        decision: 'yes',
        userid: 'abcd',
    },
    {
        name: 'abcd',
        email: 'abcd@example.com',
        decision: 'yes',
        userid: 'abcd',
    }
]

    const result = traceslist.map(o => {
        delete o.userid;
        return o;    
    })

    console.log(result);

Answer 4

This is a simple javascript problem. Also you need to convert your data to string. See the example below:

let traceslist = [
  {
    'name': 'abcd',
    'email': 'abcd@example.com',
    'decision': 'yes',
    'userid': 'abcd'
  },
  {
    'name': 'abcd',
    'email': 'abcd@example.com',
    'decision': 'yes',
    'userid': 'abcd'
  }
];

traceslist.forEach( item => delete item.userid );
console.log(traceslist);

Answer 5

Use the .map array method to remove the userid from every item in your array.

traceslist = traceslist.map(item => {
  delete item.userid;
  return item;
});

By the way, it's not angular related so your title and tag is a little misleading. An array is the same in pure javascript.