such as the title: when I was reading , an article about vuex , I found a code
.[type.DONE_TODO](state,id){
    //...
}? How does it work?
 I made a bold conjecture based on ordinary function expressions: 
 [], which refers to an attribute variable of an object, combined with the following function expression writing, forms a variable function expression. 
 I wonder if that"s what it means? 
