📅  最后修改于: 2022-03-11 15:01:42.110000             🧑  作者: Mango
//you can add custom properties to the JS arrays
//length won't change
const arr = [ 1, 2, 3, 4 ];
arr.greeting = 'Hello, world!';
console.log(arr.length); // 4
console.log(arr.greeting); // Hello, world!