`js const name = "Lydia Hallie"; const age = 21; console.log(Number.isNaN(name)); console.log(Number.isNaN(age)); console.log(isNaN(name)); console.log(isNaN(age)); ` 参考 - ...

`js const randomValue = 21; function getInfo() { console.log(typeof randomValue); const randomValue = "Lydia Hallie"; } getInfo(); ` 参考 [const](https://developer.moz ...

`js const myPromise = Promise.resolve("Woah some cool data"); (async () => { try { console.log(await myPromise); } catch { throw new Error(Oops didn't work); } finally { ...

`js const emojis = ["🥑", ["✨", "✨", ["🍕", "🍕"]]]; console.log(emojis.flat(1)); ` A: ['🥑', ['✨', '✨', ['🍕', '🍕']]] B: ['🥑', '✨', '✨', ['🍕', '🍕']] C: ['🥑', ['✨', '✨', ' ...

`js class Counter { constructor() { this.count = 0; } increment() { this.count++; } } const counterOne = new Counter(); counterOne.increment(); counterOne.incremen ...

`js const myPromise = Promise.resolve(Promise.resolve("Promise!")); function funcOne() { myPromise.then(res => res).then(res => console.log(res)); setTimeout(() => console.log("Timeout ...

`js const handler = { set: () => console.log("Added a new property!"), get: () => console.log("Accessed a property!") }; const person = new Proxy({}, handler); person.name = "Lydia ...

`js const person = { name: "Lydia Hallie" }; Object.seal(person); ` A: person.name = "Evan Bacon" B: person.age = 21 C: delete person.name D: Object.assign(person, { age: 21 ...

`js const person = { name: "Lydia Hallie", address: { street: "100 Main St" } }; Object.freeze(person); ` A: person.name = "Evan Bacon" B: delete person.address ...

`js const teams = [ { name: "Team 1", members: ["Paul", "Lisa"] }, { name: "Team 2", members: ["Laura", "Tim"] } ]; function* getMembers(members) { for (let i = 0; i < members.leng ...