Javascript function

Question

This is my first question at stackoverflow, i hope someone can help me

var filters = {
 all: function (todos) {
 return todos
 },
 active: function (todos) {
 return todos.filter(function (todo) {
 return !todo.completed
 })
 },
 completed: function (todos) {
 return todos.filter(function (todo) {
 return todo.completed
 })
 }
}
filteredTodos: function () {
 return filters[this.visibility](this.todos)
 },

Why can this "filters [this.visibility](this.todos)" use I used to be alert () so Not used alert [] () like this please help me

• bouteillebleu: Your question isn't quite clear - what exactly are you asking?
• Matt: filters[this.visibility] is not a function call, it's a property being accessed using Bracket notation - the resulting property is a function, hence the (this.todos) invocation at the end
• zer00ne: "How do that "filters[this.visibility] (this.todos) use I used to be alert() so NOT []{}(). " English please.
• ironicaldiction: @zer00ne take it easy, obviously OP is a non-native speaker...
• zer00ne: Reading the first sentence indicates OP has a grasp of the English language. @ironicaldiction I said please, I did not vote to close this question, nor have I downvoted it, so what else do you think I could do to "take it easy?" Should I edit the last sentence for OP,? I would gladly do it if what was written had any coherence.

Answer 1

filters[this.visibility](this.todos) means that filters[this.visibility] evaluates to a function.

E.g. if this.visibility = "all" then filters[this.visibility] means filters["all"]. You then call that function with the argument this.todos. It's equivalent to writing

filters.all(this.todos)

but it allows the function to be selected dynamically based on this.visibility.

• 王存露: Thank you for answering me, I want to understand