- Array.prototype.indexOf() : Returns the index of the first match in the array, or -1 if no match is found. (Accept the second parameter to specify the starting position of the search)
let arr = [1, 2, 3, 4, 5];
let index = arr.indexOf(3); // Output 2
- Array.prototype.includes() : Returns a Boolean value indicating whether the given element exists in the array. (Accept the second parameter to specify the starting position of the search) 🥇
let arr = [1, 2, 3, 4, 5];
let isIncluded = arr.includes(3); // Output true
- Array.prototype.find() : Returns the value of the first element in the array that meets the condition, otherwise returns undefined. (Accept the second parameter to specify the starting position of the search)
let arr = [{name: "Tom", age: 18}, {name: "Jerry", age: 20}];
let person = arr.find(item => item.age === 20); // Output {name: "Jerry", age: 20}
- Array.prototype.findIndex() : Returns the index of the first element in the array that meets the condition, otherwise returns -1. (Accept the second parameter to specify the starting position of the search) 🥇
let arr = [{name: "Tom", age: 18}, {name: "Jerry", age: 20}];
let index = arr.findIndex(item => item.age === 20); // Output 1
