JavaScript | How can I remove an element of an array using it's value instead of it's index?

Question

const currentMaterialsId = [1,2,3,4,5]
        
        
        const materials = {
                        0: {
                            id: 1
                        },
                        1: {
                            id: 2
                        },
                        2: {
                            id: 3
                        },
                        3: {
                            id: 4
                        },
                        4: {
                            id: 5
                        }
                    }

I am trying to remove an element in the currenMaterialsId array but when I use the index of the materials object, things don't go as planned. If I use the id as the start number in splice, it still uses that number and searches for the matching index in the array instead of the value. Please help.

here's what I have at the moment.

let sortedMaterialIndex = currentMaterialsId.sort()
        sortedMaterialIndex.splice(materialIndex, 1)
        dispatch(removeElementCurrentMaterialsArray(selectedSheet, 
        sortedMaterialIndex))

ok I'm sorry it wasn't clear guys.

What I am trying to do is remove an element in currentMaterialsId that has the same value as the id in the object materials. However, when I use the id from materials as a starting number, for example

const materialId = dashboard.sheets[selectedSheet].materialProperties[materialIndex].id
currentMaterialsId.splice(materialId, 1)

it searches currentMaterialsId array for an index that matches the passed starting number(materialId), which is what I do not want.

so let's say I want to delete 2 from currentMaterialsId, could I use splice? and if I use splice, what should I pass as a starting number?

I hope this makes my question clearer. Thanks for the responses!

rocka2q · Accepted Answer · 2021-11-02T00:43:04.143

What I am trying to do is remove an element in currentMaterialsId that has the same value as the id in the object materials.

could I use splice?

You appear to be trying to do something like this:

so.js:

const materials = {
  '0': { id: 1 },
  '1': { id: 2 },
  '2': { id: 3 },
  '3': { id: 4 },
  '4': { id: 5 }
};

console.log(materials);

// id from materials
let i = 1;
console.log(i);
let id = materials[i].id;
console.log(id);

function removeMaterialsId(id, materialsId) {
    for (let i = 0; i < materialsId.length; i++) { 
        if (materialsId[i] === id) {
            materialsId.splice(i--, 1);
        }
    }
}

let materialsId = [];

// remove materialsId elements with id from materials
console.log();
materialsId = [ 1, 2, 3, 4, 5 ];
console.log(id, materialsId);
removeMaterialsId(id, materialsId);
console.log(materialsId);

// remove materialsId elements with id from materials
console.log();
materialsId = [ 1, 2, 2, 3, 4, 2, 5 ];
console.log(id, materialsId);
removeMaterialsId(id, materialsId);
console.log(materialsId);

$ node so.js

{
  '0': { id: 1 },
  '1': { id: 2 },
  '2': { id: 3 },
  '3': { id: 4 },
  '4': { id: 5 }
}
1
2

2 [ 1, 2, 3, 4, 5 ]
[ 1, 3, 4, 5 ]

2 [ 1, 2, 2, 3, 4, 2, 5 ]
[ 1, 3, 4, 5 ]

$

score 0 · Answer 2 · answered Oct 31 '21 at 23:30

First off, perhaps you want to store your objects in an array, like this(?):

const materials = [
    {
        id: 1
    },
    {
        id: 2
    },
    {
        id: 3
    },
    {
        id: 4
    },
    {
        id: 5
    }
];

Then you can remove from array using filter:

const materialToRemove = { id: 1 }

const materialsWithOneRemoved = materials
    .filter(material => material.id !== materialToRemove.id);

Note that filter creates a new array, it does not change the existing array. You can however overwrite the existing array with a new one if you want to:

// materials like above, but with let instead of const
let materials = ...

const materialToRemove = { id: 1 }

materials = materials
    .filter(material => material.id !== materialToRemove.id);

If you want to have your objects in an object like you have in your question, you need to first convert it to an array before you can filter. You can do that using e.g. Object.values.

score 0 · Answer 3 · answered Oct 31 '21 at 23:35

Your question is far from clear, but indexOf may be a solution:

const sortedMaterialIndex = currentMaterialsId.sort();
const index = sortedMaterialIndex.indexOf(materialIndex);
if (index > -1) {
  sortedMaterialIndex.splice(index, 1);
}

See How can I remove a specific item from an array?

score 0 · Answer 4 · answered Oct 31 '21 at 23:45

0

I would recommend using the filter array function to achieve what you want.

let idToRemove = 1
let filteredMaterials = materials.filter((v) => v.id !== idToRemove);
console.log(filteredMaterials)

answered Oct 31 '21 at 23:45

Robo Rick

721
6
7

JavaScript | How can I remove an element of an array using it's value instead of it's index?

4 Answers4