javascript - myVar = {} 的作用是什么？

Question

我不明白第一行；这条线有什么作用？

phonebookEntry = {};

phonebookEntry.name = 'Oxnard Montalvo';
phonebookEntry.number = '(555) 555-5555';
phonebookEntry.phone = function() {
  console.log('Calling ' + this.name + ' at ' + this.number + '...');
};

phonebookEntry.phone();

Answer 1

此行创建一个新的空对象，没有属性

phonebookEntry = {};

没有它你就无法做到这一点:

phonebookEntry.name = 'Oxnard Montalvo';
phonebookEntry.number = '(555) 555-5555';

在 javascript 中还有另一种方法来声明等效对象:

phonebookEntry = {
    name : 'Oxnard Montalvo',
    number : '(555) 555-5555',
    phone : function() {
      console.log('Calling ' + this.name + ' at ' + this.number + '...');
    }
};

phonebookEntry.phone();

引用:MDN | Working With Objects