js怎么实现添加和删除数据

let fruits = ['apple', 'banana'];
fruits.push('orange', 'pear');
console.log(fruits); // ['apple', 'banana', 'orange', 'pear']

fruits.unshift('grape');
console.log(fruits); // ['grape', 'apple', 'banana', 'orange', 'pear']

fruits.splice(2, 0, 'melon'); // 在索引2的位置添加'melon'
console.log(fruits); // ['grape', 'apple', 'melon', 'banana', 'orange', 'pear']

let person = { name: 'Alice' };
person.age = 25;
console.log(person); // { name: 'Alice', age: 25 }

let newProps = { job: 'Engineer' };
Object.assign(person, newProps);
console.log(person); // { name: 'Alice', age: 25, job: 'Engineer' }

let lastFruit = fruits.pop();
console.log(lastFruit); // 'pear'
console.log(fruits); // ['grape', 'apple', 'melon', 'banana', 'orange']

let firstFruit = fruits.shift();
console.log(firstFruit); // 'grape'
console.log(fruits); // ['apple', 'melon', 'banana', 'orange']

fruits.splice(1, 1); // 从索引1开始，删除1个元素
console.log(fruits); // ['apple', 'banana', 'orange']

delete person.age;
console.log(person); // { name: 'Alice', job: 'Engineer' }