for( … in …) not working with array

Question

I'm somehow confused:

I have a list of commands like this:

var commands = [{"command": "read"}, {"command": "write"}, {"command": "login"}];

If I try it access one of the commands like this it works:

console.log(commands[0]["command"]); // Output is "read"
console.log(commands[0].command);    // Output is "read"

But if I try this the output is always undefined:

for(command in commands)
    console.log(command["command"]); // undefined, undefined, undefined

Answer 1

for does an array iteration in javascript, so you want:

for(command in commands)
    console.log(commands[command]["command"]);

ie, the command variable in your example is an array index, not the enumerated item from the array.