如何重构代码以避免全局作用域？

var myNamespace = {
  variable1: 'value1',
  variable2: 'value2',
  function1: function() {
    // do something
  },
  function2: function() {
    // do something
  }
};

(function() {
  var privateVariable = 'private value';

  function privateFunction() {
    // do something
  }

  // expose public API
  window.myModule = {
    publicMethod: function() {
      // access privateVariable and privateFunction
    }
  };
})();

function myFunction() {
  if (condition) {
    let localVar = 'local value';
    // do something with localVar
  }
  // localVar is not accessible here
}