Array.prototype.find()

Array.prototype.find() is a built-in method in JavaScript, which is used to search an array and return the first element that satisfies the provided testing function. This method returns undefined if the element is not found in the array.

Syntax

array.find(function (currentValue) {
  /**/
});
array.find(function (currentValue, index) {
  /**/
});
array.find(function (currentValue, index, arr) {
  /**/
});
array.find(function (currentValue, index, arr) {
  /**/
}, thisValue);

array.find((currentValue) => {
  /**/
});
array.find((currentValue, index) => {
  /**/
});
array.find((currentValue, index, arr) => {
  /**/
});
array.find((currentValue, index, arr) => {
  /**/
}, thisValue);

Parameters

• callback(currentValue, index, arr) - A function that accepts up to three arguments. The currentValue represents the current element of the array, index represents the index of the current element, and arr represents the array that find() was called upon.

• thisValue (Optional) - An object that specifies the value to be used as this when executing the callback function. If not provided, the default value is undefined.

return value

The first element of the array that satisfies the provided testing function; otherwise, undefined is returned.

Examples

const numbers = [2, 5, 7, 8, 10];
const evenNumber = numbers.find((number) => number % 2 === 0);
console.log(evenNumber); // Output: 2

In the above example, find() method is used to find the first even number in the array. The callback function checks whether the current number is divisible by 2 or not. If the current number is divisible by 2, then it is an even number, and find() returns that number.

const users = [
  { id: 1, name: "John" },
  { id: 2, name: "Jane" },
  { id: 3, name: "Alex" },
];
const user = users.find((user) => user.id === 2);
console.log(user); // Output: { id: 2, name: 'Jane' }

In the above example, find() method is used to find the object with id equal to 2 in the array of objects. The callback function checks whether the id property of the current object is equal to 2 or not. If the id property is equal to 2, then find() method returns that object.

Notes

• find() method is a built-in function of the Array object in JavaScript.

• It is used to find the first element in an array that satisfies a given condition.

• find() method takes a callback function as an argument, which is executed on each element of the array until the condition is satisfied.

• It does not modify the original array.

• It works with arrays of any data type.

• The callback function should return true if the current element satisfies the condition, and false otherwise.

• The callback function can take up to three arguments: the current element being processed, the index of the current element, and the array on which the find() method is called.

• It returns the value of the first element in the array that satisfies the condition, or undefined if no element satisfies the condition.

• If the array being searched is empty, the find() method will return undefined.

• find() method stops searching the array as soon as it finds the first element that satisfies the condition.

• It was introduced in ECMAScript 2015 (ES6), so it may not be available in older browsers.