学ぶ Finding Elements in an Array with the find() Method

Core JavaScript for Web Development

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Let's explore the find() method, including its syntax and applications, with concrete examples to illustrate its functionality.

find()

While the filter() method sifts through an array to uncover all elements meeting a condition, the find() method is tailor-made for a singular mission – discovering and retrieving the first matching element. Here's a closer look at its syntax:

array.find((element, index, array) => {
  // Callback body
});

Let's unravel the critical characteristics of the find() method:

The original array remains unaltered;
It navigates through the array, scrutinizing each element;
The method halts upon locating the initial match, returning that specific element;
Without a matching element, the method returns undefined.

Find a Task by Order

In this example, the 'find()' method retrieves the task by the 'order' key.


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const tasks = [
  { order: 1, name: "Buy groceries" },
  { order: 2, name: "Walk the dog" },
  { order: 3, name: "Read a book" },
];

const firstTask = tasks.find((element) => element.order === 1);
console.log("First task:", firstTask.name); // Output: First task: Buy groceries

const secondTask = tasks.find((element) => element.order === 2);
console.log("Second task:", secondTask.name); // Output: Second task: Walk the dog