Description of arr.find() and arr.filter() functions

arr.find()Is a method of JavaScript arrays, used to find the first element in the array that meets the criteria.

const arr = [2, 4, 6, 8];
const found = arr.find(element => element > 5);
console.log(found); // 6

In addition to simple comparisons, we can also use find()the method to build more complex search conditions. For example

const people = [
  { name: '张三', age: 25, gender: 'male' },
  { name: '李四', age: 30, gender: 'male' },
  { name: '王五', age: 28, gender: 'female' }
];
const found = people.find(person => person.gender === 'female' && person.age > 25);
console.log(found); // {name: "王五", age: 28, gender: "female"}

arr.filter() is to find all eligible records and display them in a new array

const numbers = [1, 2, 3, 4, 5];
const evenNumbers = numbers.filter(number => number % 2 === 0);

console.log(evenNumbers); // [2, 4]

A more complex example:

const people = [
  { name: '张三', age: 25, gender: 'male' },
  { name: '李四', age: 30, gender: 'male' },
  { name: '王五', age: 28, gender: 'female' }
];
const found = people.filter(person => person.gender === 'female' && person.age > 25);
console.log(found); //[{name: "王五", age: 28, gender: "female"},{ name: '王五', age: 28, gender: 'female' }]