JS Calling Object Property by Variable

问题

When I have an object and I want to refer to a property within it, I can use e.g.

objectName.propertyName 

and when I have a "subproperty" I can use

objectName.propertyName.propertyName

But how can I use a variable with this syntax ?

objectName.myvar.propertyName

Obviously this does not work. The variable is interpreted as a string itself and calls for the value with the key: "myvar".

How do I have to declare the variable using this syntax to be used like this:

var myvar = qwertz; objectName.myvar.propertyName 

and be interpreted as

var myvar = qwertz; objectName.qwertz.propertyName 

回答1:

Use the bracket notation:

var myvar = 'qwertz';
var result = objectName[myvar].propertyName; 
// equivalent to objectName.qwertz.propertyName

来源：https://stackoverflow.com/questions/21799972/js-calling-object-property-by-variable