javascript 'use strict' 和 Object.defineProperty setter

Question

'use strict';

class DataClass{

        constructor(name){
            this.name = name;

            Object.defineProperties(this, {
                _archives :{
                    value : []

                },
                temperature : {

                    enumerable : true,
                    set : function(value){

                        // error message : InternalError: too much recursion
                        //this.temperature = value;
                        //error message  in case of 'use strict' : ReferenceError: assignment to undeclared variable temperature
                        temperature = value;
                        this._archives.push(value);

                    },
                    get : function(){
                        return ' yyy ';
                    } 
                },

            });
        }



 }



 var dataClass1 = new DataClass('giovanni');
 dataClass1.temperature = 45;
 console.log(dataClass1.temperature);

当我尝试在严格模式下运行这段代码时，我总是得到这个错误ReferenceError: assignment to undeclared variable temperature 我想了解解决此问题的最佳方法

Answer 1

当您使用 'use strict' 时，您不能使用未声明的变量。在 "this.name = name;" 之后放 "var temperature;"

'use strict';

class DataClass{

        constructor(name){
            this.name = name;
            var temperature; // <- private variable, completely different from the public one.
            Object.defineProperties(this, {
                _archives :{
                    value : []

                },
                temperature : { // <- public variable Object.temperature, internally this.temperature

                    enumerable : true,
                    set : function(value){

                        // error message : InternalError: too much recursion
                        //this.temperature = value; <-- Call the set again, that's why the loop.
                        //error message  in case of 'use strict' : ReferenceError: assignment to undeclared variable temperature
                        temperature = value;
                        this._archives.push(value);

                    },
                    get : function(){
                        return ' yyy ';
                    } 
                },

            });
        }



 }



 var dataClass1 = new DataClass('giovanni');
 dataClass1.temperature = 45;
 console.log(dataClass1.temperature);

javascript 'use strict' 和 Object.defineProperty setter

javascript 'use strict' and and Object.defineProperty setter

javascript

class

es6-class