下面的例子展示了如何修改基本类型对象的 constructor 属性的值。只有 true, 1 和 “test” 的不受影响，因为创建他们的是只读的原生构造函数（native constructors）。这个例子也说明了依赖一个对象的 constructor 属性并不安全。
    代码:

    2. function Type() {};
    4. var types = [
    5.     new Array,
    6.     [],
    7.     new Boolean,
    8.     true,    // remains unchanged 
    9.     new Error,
    10.     new Function,
    11.     function () {},
    12.     Math,
    13.     new Number,
    14.     1,  // remains unchanged
    15.     new Object,
    16.     {},
    17.     new RegExp,
    18.     /(?:)/,
    19.     new String,
    20.     "test"   // remians unchanged
    22. ]
    24. types.forEach((value)=>{
    25.     console.log( (value instanceof Type) + " constructor:  " + value.constructor + " \n")
    26. })
    28. for (var i = 0; i<types.length ; i++){
    29.     types[i].constructor = Type ;
    30.     types[i] = [types[i].constructor , types[i] instanceof Type ,types[i].toString() ];
    31. }
    34. console.log("修改之后：\n")
    35. console.log(types.join("\n"))

    打印结果:

    1. false constructor:  function Array() { [native code] } 
    3. false constructor:  function Array() { [native code] } 
    5. false constructor:  function Boolean() { [native code] } 
    7. false constructor:  function Boolean() { [native code] } 
    9. false constructor:  function Error() { [native code] } 
    11. false constructor:  function Function() { [native code] } 
    13. false constructor:  function Function() { [native code] } 
    15. false constructor:  function Object() { [native code] } 
    17. false constructor:  function Number() { [native code] } 
    19. false constructor:  function Number() { [native code] } 
    21. false constructor:  function Object() { [native code] } 
    23. false constructor:  function Object() { [native code] } 
    25. false constructor:  function RegExp() { [native code] } 
    27. false constructor:  function RegExp() { [native code] } 
    29. false constructor:  function String() { [native code] } 
    31. false constructor:  function String() { [native code] } 
    33. 修改之后：
    35. function Type() {},false,
    36. function Type() {},false,
    37. function Type() {},false,false
    38. function Boolean() { [native code] },false,true
    39. function Type() {},false,Error
    40. function Type() {},false,function anonymous(
    41. ) {
    43. }
    44. function Type() {},false,function () {}
    45. function Type() {},false,[object Math]
    46. function Type() {},false,0
    47. function Number() { [native code] },false,1
    48. function Type() {},false,[object Object]
    49. function Type() {},false,[object Object]
    50. function Type() {},false,/(?:)/
    51. function Type() {},false,/(?:)/
    52. function Type() {},false,
    53. function String() { [native code] },false,test