155个JavaScript基础问题（56-65）

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56. 输出是什么？

const set = new Set([1, 1, 2, 3, 4]);

console.log(set);

57. 输出是什么？

// counter.js
let counter = 10;
export default counter;

// index.js
import myCounter from "./counter";

myCounter += 1;

console.log(myCounter);

58. 输出是什么？

const name = "Lydia";
age = 21;

console.log(delete name);
console.log(delete age);

59. 输出是什么？

const numbers = [1, 2, 3, 4, 5];
const [y] = numbers;

console.log(y);

60. 输出是什么？

const user = { name: "Lydia", age: 21 };
const admin = { admin: true, ...user };

console.log(admin);

61. 输出是什么？

const person = { name: "Lydia" };

Object.defineProperty(person, "age", { value: 21 });

console.log(person);
console.log(Object.keys(person));

62. 输出是什么？

const settings = {
  username: "lydiahallie",
  level: 19,
  health: 90
};

const data = JSON.stringify(settings, ["level", "health"]);
console.log(data);

63. 输出是什么？

let num = 10;

const increaseNumber = () => num++;
const increasePassedNumber = number => number++;

const num1 = increaseNumber();
const num2 = increasePassedNumber(num1);

console.log(num1);
console.log(num2);

64. 输出是什么？

const value = { number: 10 };

const multiply = (x = { ...value }) => {
  console.log(x.number *= 2);
};

multiply();
multiply();
multiply(value);
multiply(value);

65. 输出是什么？

[1, 2, 3, 4].reduce((x, y) => console.log(x, y));

题目来源

github.com/lydiahallie…

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