常见的前端开发场景中如何使用闭包进行剖析和分析

function addButtonHandlers() {
  var buttons = document.getElementsByTagName("button");
  for (var i = 0; i < buttons.length; i++) {
    var button = buttons[i];
    button.addEventListener("click", createClickHandler(i));
  }
}

function createClickHandler(index) {
  return function() {
    console.log(index);
  };
}

function createCounter() {
  var count = 0;

  return {
    increment: function() {
      count++;
    },
    decrement: function() {
      count--;
    },
    getCount: function() {
      return count;
    }
  };
}

var counter = createCounter();
counter.increment();
console.log(counter.getCount()); // 输出 1

var MyModule = (function() {
  var privateVariable = "Private";
  var publicVariable = "Public";

  function privateMethod() {
    console.log("Private method");
  }

  function publicMethod() {
    console.log("Public method");
  }

  return {
    publicVariable: publicVariable,
    publicMethod: publicMethod
  };
})();

console.log(MyModule.publicVariable); // 输出 "Public"
MyModule.publicMethod(); // 输出 "Public method"

for (var i = 0; i < 5; i++) {
  setTimeout(function() {
    console.log(i);
  }, 1000);
}

for (var i = 0; i < 5; i++) {
  (function(i) {
    setTimeout(function() {
      console.log(i);
    }, 1000);
  })(i);
}