Javascript array/object syntax fail

Question

Why do I get this error with this code: Uncaught SyntaxError: Unexpected token { on line 1.

var cube_points = {
    {'x' : 100, 'y' : 100, 'z' : 100},
    {'x' : 100, 'y' : 100, 'z' : -100},
    {'x' : -100, 'y' : 100, 'z' : -100},
    {'x' : -100, 'y' : 100, 'z' : 100},
    {'x' : 100, 'y' : -100, 'z' : 100},
    {'x' : 100, 'y' : -100, 'z' : -100},
    {'x' : -100, 'y' : -100, 'z' : -100},
    {'x' : -100, 'y' : -100, 'z' : 100}
};

ErikE · Accepted Answer · 2011-05-22 19:10:08Z

7

Your outer object's elements have values but no keys. If you want an array of cube points, use the square bracket to denote an array literal:

var cube_points = [
    {'x' : 100, 'y' : 100, 'z' : 100},
    {'x' : 100, 'y' : 100, 'z' : -100},
    {'x' : -100, 'y' : 100, 'z' : -100},
    {'x' : -100, 'y' : 100, 'z' : 100},
    {'x' : 100, 'y' : -100, 'z' : 100},
    {'x' : 100, 'y' : -100, 'z' : -100},
    {'x' : -100, 'y' : -100, 'z' : -100},
    {'x' : -100, 'y' : -100, 'z' : 100}
];

If you want an object, give the items a key. This could be numbers or letters or even objects:

var cube_points = {
    1: {'x' : 100, 'y' : 100, 'z' : 100},
    2: {'x' : 100, 'y' : 100, 'z' : -100},
    'q': {'x' : -100, 'y' : 100, 'z' : -100},
    'z': {'x' : -100, 'y' : 100, 'z' : 100},
    '25': {'x' : 100, 'y' : -100, 'z' : 100},
    '26': {'x' : 100, 'y' : -100, 'z' : -100},
    10: {'x' : -100, 'y' : -100, 'z' : -100},
    11: {'x' : -100, 'y' : -100, 'z' : 100}
};

Obviously, using an object necessitates some kind of orderly system of key selection. Since your points aren't easily named, you're better off using an array. But I wanted to show what object literal notation would look like.

edited May 22, 2011 at 19:10

answered May 20, 2011 at 21:00

ErikE

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2 Comments

pimvdb Over a year ago

I honestly think starting at 0 in the object is more consistent.

ErikE Over a year ago

It's an object. You can use letters or numbers or objects as keys. But just to put a lid on the critics, I'll make some adjustments.

Darin Dimitrov · Accepted Answer · 2011-05-20 20:59:12Z

7

What you have is not a valid javascript object definition. {} denotes object, so inside you should have properties, not other {}. What you need is an array which is denoted with []:

var cube_points = [
    {'x' : 100, 'y' : 100, 'z' : 100},
    {'x' : 100, 'y' : 100, 'z' : -100},
    {'x' : -100, 'y' : 100, 'z' : -100},
    {'x' : -100, 'y' : 100, 'z' : 100},
    {'x' : 100, 'y' : -100, 'z' : 100},
    {'x' : 100, 'y' : -100, 'z' : -100},
    {'x' : -100, 'y' : -100, 'z' : -100},
    {'x' : -100, 'y' : -100, 'z' : 100}
];

which you could then access like this:

cube_points[2].y

answered May 20, 2011 at 20:59

Darin Dimitrov

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