JS 地图

let funnymap = new map();

funnymap.set('a', 1); // string keyfunnymap.set(2, 'two'); // number keyfunnymap.set(true, 'yes'); // boolean keyfunnymap.set({name: 'obj'}, 'object'); // object key// funny examplefunnymap.set('knock-knock', 'who’s there?');

console.log(funnymap.get('a')); // 1console.log(funnymap.get(2)); // twoconsole.log(funnymap.get(true)); // yes// funny exampleconsole.log(funnymap.get('knock-knock')); // who’s there?

console.log(funnymap.has('a')); // trueconsole.log(funnymap.has(42)); // false// funny exampleconsole.log(funnymap.has('chicken')); // false (it crossed the road)

funnymap.delete('a');console.log(funnymap.has('a')); // false// funny examplefunnymap.delete('knock-knock');console.log(funnymap.get('knock-knock')); // undefined (no one answered)

console.log(funnymap.size); // 3 after deletion// funny exampleconsole.log(`the map has ${funnymap.size} jokes left.`);

funnymap.clear();console.log(funnymap.size); // 0// funny exampleconsole.log(`all jokes are cleared from the map.`);

funnymap.set('banana', 'yellow');funnymap.set('apple', 'red');funnymap.set('grape', 'purple');// iterating over keysfor (let key of funnymap.keys()) {    console.log(`key: ${key}`);}// iterating over valuesfor (let value of funnymap.values()) {    console.log(`value: ${value}`);}// iterating over entriesfor (let [key, value] of funnymap.entries()) {    console.log(`key: ${key}, value: ${value}`);}// funny examplefunnymap.set('dad joke', 'what do you call fake spaghetti? an impasta!');for (let [key, value] of funnymap.entries()) {    console.log(`here’s a ${key}: ${value}`);}

funnymap.foreach((value, key) => {    console.log(`key: ${key}, value: ${value}`);});// funny examplefunnymap.set('bad pun', 'i’m reading a book on anti-gravity. it’s impossible to put down!');funnymap.foreach((value, key) => {    console.log(`here’s a ${key}: ${value}`);});

let jokeText = "Why did the scarecrow win an award? Because he was outstanding in his field!";// Splitting text into wordslet words = jokeText.split(/\W+/);let wordCount = new Map();words.forEach(word => {    word = word.toLowerCase();    if (wordCount.has(word)) {        wordCount.set(word, wordCount.get(word) + 1);    } else {        wordCount.set(word, 1);    }});wordCount.forEach((count, word) => {    console.log(`Word: ${word}, Count: ${count}`);});// Funny exampleconsole.log('Word counts in our joke:');wordCount.forEach((count, word) => {    console.log(`"${word}": ${count} times`);});