js访问对象键值属性

Say you have this object:

说你有这个对象：

const dog = {  name : 'Roger'}

To get the value of the name property, you can use the dot syntax, like this:

要获取name属性的值，可以使用点语法，如下所示：

dog . name

Or you can use the square brackets property accessor syntax:

或者，您可以使用方括号属性访问器语法：

dog [ 'name' ]

This is especially useful when a property has not a valid variable name, like the name:

这是特别有用当一个属性没有一个有效的变量名，如the name ：

const dog = {  'the name' : 'Roger'}dog [ 'the name' ]

and it’s also very useful when you don’t know the property name beforehand, and you evaluate it programmatically, like in this example that loops through the object property names:

当您事先不知道属性名称并且以编程方式对其进行评估时，它也非常有用，例如在此示例中循​​环遍历对象属性名称：

const dog = {  'the name' : 'Roger'}for ( const [ key , value ] of Object. entries ( dog )) {  console . log ( value )}

翻译自:

js访问对象键值属性