JavaScript - arrays braces vs brackets

The first one doesn't create an array, it creates a new empty object. The second and third create a new array and they are equivalent.

Here's a simple type check:

// ONLINE-RUNNER:browser;

var array1 = {};          // creates new empty object
var array2 = [];          // creates new empty array
var array3 = new Array(); // creates new empty array


// Check if array:

console.log(Array.isArray(array1)); // false
console.log(Array.isArray(array2)); // true
console.log(Array.isArray(array3)); // true

See also

1. JavaScript - check if variable is array type