What means {} in javascript

Question

I was researching some sample code and couldn't understand this line of code

var foo = {};

As far as i could see it is used as a kind of arry where the index is a string entered by the user instead of 0,1,2,... etc. Can explain/confirm this. Cheers!

For future reference, those are referred to as `curly braces`. — Ashley Davies, Jan 19 '14 at 15:30
@AshleyDavies I always thought they were smiley mustaches. ;) — Anil, Jan 19 '14 at 15:33

score 2 · Accepted Answer · answered Jan 19 '14 at 15:29

2

That is an object literal. It can be used like an associate array in other languages, but javascript objects tend to do much more. It does use key/value pairs, but the values can be functions, other objects, arrays or anything.

answered Jan 19 '14 at 15:29

m59

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score 1 · Answer 2 · edited May 23 '17 at 10:28

1

declaring a javascript variable as {} is basically creating an empty object.

See this answer: Create an empty object in JavaScript with {} or new Object()?

edited May 23 '17 at 10:28

Community

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answered Jan 19 '14 at 15:30

Mark Redman

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score 0 · Answer 3 · answered Jan 19 '14 at 15:30

0

{} represents an empty object.

To initialize an object you can do something like this:

var foo = {
    bar: "test";
}

alert(foo.bar); // alerts "test"

answered Jan 19 '14 at 15:30

Kenneth

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score 0 · Answer 4 · answered Jan 19 '14 at 15:31

This is the notation for creating an empty object and assigning it to foo.

The 'array' like behavior is that JavaScript objects act like associative arrays - mappings between strings and properties, which can be Numbers, String, etc. or other Objects.

I suggest you read "JavaScript The Good Parts"

What means {} in javascript

4 Answers4