Get the property value a javascript object is easy:
var t = {a:"hi"}
t.a //print "hi"
But for the next object, the same idea does not work:
var t = {0:"hi"}
t.0 //Uncaught SyntaxError: Unexpected number
How to get value of t.0?
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1 Answer
Use t['0']. If a key can't be syntactically placed after the dot, you need to use this syntax.
Your first example could be similarly rewritten to t['hi'].
It's worth pointing out that the key is not a number at all. It's a string with the value '0'.
8 Comments
zerkms
"If a key can't be syntactically placed after the dot" --- +1'd, but it would be even more helpful if the rules or at least a tiny excerpt of those was provided on what is syntactically valid to be used there and what is not.
Hailwood
@zerkms "If the key cannot be used a valid variable identifier (
var not-valid; for example) then it must be accessed via the square bracket syntax"? I'm curious how you would provide the rules?
Spencer Wieczorek
@zerkms It's invalid syntax when using dots for a variable to start with a number, it includes properties as well.
zerkms
@SpencerWieczorek well, I can check the standard with no problem, my suggestion addressed the answer improvement
MinusFour
The expression inside the square brackets need not be a string,
t[0] is also valid. What's important to notice is that square brackets take an expression, while the dot syntax expects a valid identifier |