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.
When you begin a line with {
JavaScript thinks it starts a block statement, not an object literal. Parenthesize it and you will be okay.
var arr = []
({}).toString.apply(arr) // TypeError: object is not a function
To work code must contains semicolons ;
after each row
var arr = [];
({}).toString.apply(arr); // works OK
Andrew D. 2012-04-04 07:10