A variable declaration and assignment is possible to do within a line, but it seems not possible to do with an array, why?
var variable1 = 5; // Works
var array1[0] = 5; // Doesn't work
var array2 = []; // Works
array2[0] = 5;
5 Answers
An array initialiser has the form:
var a = [5];
When you do:
var array1[0]
then the interpretter sees var and expects it to be followed by an identifier. However, array1[0] is not a valid identifier due to the "[" and "]" characters. If they were, you'd have a variable named array1[0] that has the value 5.
Comments
var array1 = [5]; initializes array1 to an array literal with a single element 5.
Note that array1 is not a constant array, elements can be pushed, read, changed, etc.
The above line has the same effect as
var array1 = [];
array1[0] = 5;
Comments
You almost had it:
var array2 = [5];
Comments
You can't use var when pushing to an array because it interprets as "array1[0]" - using characters that aren't allowed, but also you need to set the array first
var array1 = [];
array1[0] = 5; // Yes it does
console.log(array1);
Comments
Because it's just the wrong way, i guess.
var array1 = [5];
var array2 = [3,4,5];
is the way you wanna do it.
array1[0], it is trying to set the zeroth element ofarray1, which does not existvar array1 = [];