Differences between js object attributes through vertices (.) and square brackets ([])

The following small series will introduce the differences between vertices (.) and square brackets ([]) in js object attributes. I think this is quite good. Now I will share it with you and give you a reference. Let's take a look at the query and setting of JS object attributes]

You can use the dot (.) or square brackets ([]) operator to obtain the attribute value. The left side of the operator is an expression that returns an object. For vertices (.), the right side must be a simple identifier named after the property name. For square brackets ([]), square brackets must be an expression that calculates the result as a string. This string is the name of the attribute: