Check if a value exists in an object within an array in JavaScript

Sometimes you want to check if a certain value exists in an object within an array. For example, if the value exists, you might want to write it to the database。

Is “Tanaka-kun” in this list？

const list = [
  {
    age: 5,
    name: "Tanaka-kun"
  },
  {
    age: 10,
    name: "Suzuki-kun"
  },
  {
    age: 10,
    name: "Watabe-kun"
  }
];

You could use a loop, but let’s do it smartly with Array.prototype.some()。

Array.prototype.some() only works on arrays, so if you have an empty array, you can still use it。

So, here’s how you can do it：

const list = [
  {
    age: 5,
    name: "Tanaka-kun"
  },
  {
    age: 10,
    name: "Suzuki-kun"
  },
  {
    age: 10,
    name: "Watabe-kun"
  }
];
const someArray = [];
for (const e of list) {
  someArray.push(e.name);
}
const result = someArray.some((value) => value === "Tanaka-kun");
console.log(result);

>> true

I was able to check it properly!