How to determine if Javascript array contains an object with an attribute that equals a given value?

Question

I have an array like

vendors = [{
    Name: \'Magenic\',
    ID: \'ABC\'
  },
  {
    Name: \'Microsoft\',
    ID: \'DEF\'
  } // and so on... 
];


        

Answer 1

As the OP has asked the question if the key exists or not.

A more elegant solution that will return boolean using ES6 reduce function can be

const magenicVendorExists =  vendors.reduce((accumulator, vendor) => (accumulator||vendor.Name === "Magenic"), false);

Note: The initial parameter of reduce is a false and if the array has the key it will return true.

Hope it helps for better and cleaner code implementation

Answer 2

var without2 = (arr, args) => arr.filter(v => v.id !== args.id); Example:

without2([{id:1},{id:1},{id:2}],{id:2})

Result: without2([{id:1},{id:1},{id:2}],{id:2})

Answer 3

const VENDORS = [{ Name: 'Magenic', ID: 'ABC' }, { Name: 'Microsoft', ID: 'DEF' }];

console.log(_.some(VENDORS, ['Name', 'Magenic']));

<script src="https://cdn.jsdelivr.net/npm/lodash@4.17.20/lodash.min.js"></script>

Answer 4

You can use lodash. If lodash library is too heavy for your application consider chunking out unnecessary function not used.

let newArray = filter(_this.props.ArrayOne, function(item) {
                    return find(_this.props.ArrayTwo, {"speciesId": item.speciesId});
                });

This is just one way to do this. Another one can be:

var newArray=  [];
     _.filter(ArrayOne, function(item) {
                        return AllSpecies.forEach(function(cItem){
                            if (cItem.speciesId == item.speciesId){
                            newArray.push(item);
                          }
                        }) 
                    });

console.log(arr);

The above example can also be rewritten without using any libraries like:

var newArray=  [];
ArrayOne.filter(function(item) {
                return ArrayTwo.forEach(function(cItem){
                    if (cItem.speciesId == item.speciesId){
                    newArray.push(item);
                  }
                }) 
            });
console.log(arr);

Hope my answer helps.

Answer 5

const a = [{one:2},{two:2},{two:4}]
const b = a.filter(val => "two" in val).length;
if (b) {
   ...
}

Answer 6

Alternatively you can do:

const find = (key, needle) => return !!~vendors.findIndex(v => (v[key] === needle));