JSLint is giving me this error:
Problem at line 11 character 33: Use the array literal notation [].
var myArray = new Array();
What is array literal notation and why does it want me to use it instead?
It shows here that new Array(); should work fine... is there something I'm missing?
array literal notation is where you define a new array using just empty brackets. In your example:
var myArray = [];
It is the "new" way of defining arrays, and I suppose it is shorter/cleaner.
The examples below explain the difference between them:
var a = [], // these are the same
b = new Array(), // a and b are arrays with length 0
c = ['foo', 'bar'], // these are the same
d = new Array('foo', 'bar'), // c and d are arrays with 2 strings
// these are different:
e = [3], // e.length == 1, e[0] == 3
f = new Array(3); // f.length == 3, f[0] == undefined
Reference: What’s the difference between “Array()” and “[]” while declaring a JavaScript array?
[]. The reason this is better is that it's safer because someone could potentially overwrite the window.Array constructor but not the literal.
var a: string[] = [];.See also: What’s wrong with var x = new Array();
Aside from the Crockford argument, I believe it is also due to the fact that other languages have similar data structures that happen to use the same syntax; for example, Python has lists and dictionaries; see the following examples:
// this is a Python list
a = [66.25, 333, 333, 1, 1234.5]
// this is a Python dictionary
tel = {'jack': 4098, 'sape': 4139}
Isn't it neat how Python is also grammatically correct Javascript? (yes, the ending semi-colons are missing, but those aren't required for Javascript, either)
Thus, by reusing common paradigms in programming, we save everyone from having to relearn something that shouldn't have to.
Aside from the Crockford argument, jsPerf says that it's faster. http://jsperf.com/new-vs-literal-array-declaration
After looking at @ecMode jsperf, I did some further tests.
When using push to add to the array new Array() is considerably faster on Chrome:
http://jsperf.com/new-vs-literal-array-declaration/2
Using index to add is slightly faster for [].
