I\'m working with some people are are used to making \"associative arrays\" in J
ID: 647133 • Letter: I
Question
I'm working with some people are are used to making "associative arrays" in JavaScript like this:
var arr = new Array();
arr.prop_1 = "asdf";
or
arr['prop 2'] = "1234";
It works just like an object because it is. for...in loops can be used and accessing the properties is fine using a dot or a square brace. the lack of native array methods seems not to be lamented. I find it sort of semantically irritating however. Maybe I'm being picky, but I want a good argument for arresting the use of this syntax, but I can't understand how to start. Any suggestions?
Explanation / Answer
Which do you think looks cleaner?
object = new Array();
object.prop1 = 1;
object.prop2 = 2;
object.prop3 = 3;
or
object = {
prop1: 1,
prop2: 2,
prop3: 3
}
?
Also, if you do something like this:
if (object.length === undefined) object.length = 10
object.length // 0
Then object.length will still be 0, which is definitely not what you would expect. You might think this is just a fake example that will never come up in real life, but look at this:
words = 'You should join our club because it is a club'.split(' ')
obj = new Array()
words.forEach(function(x) {
if (obj[x] === undefined) obj[x] = 0
obj[x] ++
})
for (var x in obj) console.log(x, obj[x])
This will log:
You 1
should 1
join NaN // <-- oops
our 1
club 2
because 1
it 1
is 1
a 1
Alternatively, you could make an analogy to any other object, like a function:
object = function() {}
object.prop1 = 1;
// ...
Anyone could immediately tell you that that is wrong, and using an array is just as wrong.