using .find() method but get undefined in JavaScript

Question

Here I'm defining a function using .find() method, and it should return { name: 'Adidas', price: 95 }.Anyone knows why it returns 'undefined' instead?

    var shoes = [
  { name: 'Nike', price: 200 },
  { name: 'Red Wings', price: 250 },
  { name: 'Vans', price: 150 },
  { name: 'Converse', price: 160 },
  { name: 'Reebok', price: 130 },
  { name: 'New Balance', price: 175 },
  { name: 'Adidas', price: 95 },
  { name: 'Keds', price: 140 },
  { name: 'Crocs', price: 135 }
];



const findWhere = function (array, criteria) {

  const key = Object.keys(criteria)[0];
  criteria = criteria[key];

  const result = array.find(ele => ele.key === criteria);
  return result;
};

const myShoe = findWhere(shoes, {price: 95});
console.log(myShoe);

You're checking ele.key, not ele[key]. Since that field doesn't exist, it will never find a match. — Etheryte
– Etheryte, Commented May 19, 2022 at 20:11

k.tten · Accepted Answer · 2022-05-19 20:12:34Z

5

You've used ele.key which accesses the literal key property on ele.

And since there is no key property on any of these objects:

{ name: 'Crocs', price: 135 }

ele.key is always undefined, meaning you get no matches.

Use brackets like you had earlier (criteria = criteria[key];):

const result = array.find(ele => ele[key] === criteria);
//                                  ^   ^

answered May 19, 2022 at 20:12

k.tten

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Comments

Saleh Rahimzadeh · Accepted Answer · 2022-05-19 20:24:44Z

1

Replace ele.key to ele[key]

const result = array.find(ele => ele[key] === criteria);

answered May 19, 2022 at 20:24

Saleh Rahimzadeh

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