为什么 `{}.toString.apply(array)` 不起作用？

Question

Usually, when I want to check the type of an object (whether it's an array, a NodeList, or whatever), I use the following:

var arr = [] // I don't do this, but it's for the sake of the example
var obj = {}
obj.toString.apply(arr) // This works

The question is: why can I not do the following?

var arr = []
{}.toString.apply(arr) // Syntax error: Unexpected token .

I don't get where the syntax error is.

I can do something approaching with [] though, the following works:

var nodeList = document.getElementsByClassName('foo')
[].forEach.call(nodeList, function(bar) { console.log(bar) }) // Works

So... I'm confused.

Answer 1

When you begin a line with { JavaScript thinks it starts a block statement, not an object literal. Parenthesize it and you will be okay.