functionmakeCounter() {letcount =0;returnfunction() {return++count; };}constcounter =makeCounter();console.log(counter());// 1console.log(counter());// 2 现实:如果没有闭包,我们就会像 1995 年那样,陷入状态传递的泥潭。 3. Pr...
// Example of a closurefunctioncreateCounter(){letcount =0;returnfunction(){count++;returncount;};} constcounter = createCounter();console.log(counter());// 1console.log(counter());// 2 用例:闭包非常适合在事件处理程序中维护状态、创建...
let counter = 0; const intervalId = setInterval(() => { console.log('Hello World'); counter += 1; if (counter === 5) { console.log('Done'); clearInterval(intervalId); } }, 1000); 我将counter值作为0启动,然后启动一个setInterval调用同时捕获它的id。 延迟功能将打印消息并每次递增计...
AI代码解释 functioncreateCounter(){letcount=0;return{increment:function(){count++;},decrement:function(){count--;},getCount:function(){returncount;}};}constcounter=createCounter();counter.increment();counter.increment();console.log(counter.getCount());// 输出: 2 在这个例子中,createCounter函数...
function createCounter() { let count = 0; return function () { return ++count; }; } const counter = createCounter(); console.log(counter()); // 输出: 1 console.log(counter()); // 输出: 2 7、函数组合 函数组合是将两个或多个函数组合成一个新函数的过程。它有助于代码重用。 代码语言...
// lib.js export let counter = 3; export function incCounter() { counter++; } // main.js import { counter, incCounter } from './lib'; console.log(counter); // 3 incCounter(); console.log(counter); // 4 上面代码说明,ES 6 模块输入的变量counter是活的,完全反应其所在模块lib.js...
let item = helpText[i]; document.getElementById(item.id).onfocus = function() { showHelp(item.help); } } } setupHelp(); 1. 2. 3. 4. 5. 6. 7. 8. 9. 10. 11. 12. 13. 14. 15. 16. 17. 18. 19. 例如,在创建新的对象或者类时,方法通常应该关联于对象的原型,而不是定义到对象...
Example The inner functionplus()has access to thecountervariable in the parent function: functionadd() { letcounter =0; functionplus() {counter +=1;} plus(); returncounter; } Try it Yourself » This could have solved the counter dilemma, if we could reach theplus()function from the ...
Example: Find Factorial of a Number Now, let's see an example of how we can use recursion to find the factorial of a number. // recursive function function factorial(num) { // base case // recurse only if num is greater than 0 if (num > 1) { return num * factorial(num - 1)...
lethasOwnProperty=Object.prototype.hasOwnProperty;if(hasOwnProperty.call(object,'foo')) {console.log('has property foo'); } 1. 2. 3. 4. 但是,我们现在可以这样写: 复制 object.hasOwnProperty('foo') 1. 请记住,JavaScript是一种动态语言。我们可以将属性添加到任何对象。因此,HasownProperty()可以...