If I want to make an array that is say of length 3 using bracket notation, should I just write: var foo = [,,];
I was more used to writing: var foo = new Array(3);
I noticed that if I removed one , that my code still worked which is surprising because I am accessing all 3 elements after assigning them. How is it that it would still work?
if u do
a = []
a[3] = 100
the indices 0,1,2 will be filled in with undefined for u. u do not have to set a specific array length before using certain indices. array will grow as u use it.
all these are the same:
a = [,,,]
b = []
b.length = 3
c = new Array(3)
d = []
d[2] = undefined
[,,,] makes an array of 3 elements. i kno its weird. i dont think theres an advantage, maybe slightly faster if it can do allocation all at once instead of one index at a time. but thats a micro optimization.a = [] makes an array of length 0
Arraywith specific lengthn, you can useArray(n).join().split(','). So, if you need anArraycontaining 100 empty elements:Array(100).join().split(',').new Array(100)?Array(100)you can't use methods likemap. E.g.Array(100).join().split(',').map(function(){return 1;})returns anArraycontaining 100 elements with value 1,Array(10).map(function(){return 1;})anArraycontaining 100 elements with valueundefined