JavaScript闭包实现延迟求值与性能优化示例

var bigFunctionA = function(){
  var s = 0;
  for(var i=0;i<10000;i++){
    s += i;
    }
  return s;
  }
var bigFunctionB = function(){
  var s = "a";
  for(var i=0;i<100;i++){
    s += i;
    }
  return s;
  }
function RandomThrow(s1,s2){
  if(Math.random()>0.5){
    return s1();
    return s2();
    }
  }
//只对一个函数进行求值,在计算量比较大的情况下,能明显提高效率;
//闭包与延迟求值
RandomThrow(bigFunctionA,bigFunctionB);