Enumeration
The for in
statement can loop over all of the property names in an object. The enumeration will include functions and prototype properties.
var fruit = {
apple: 2,
orange:5,
pear:1
},
sentence = "I have ",
quantity;
for (kind in fruit){
quantity = fruit[kind];
sentence += quantity+" "+kind+
(quantity===1?"":"s")+
", ";
}
// The following line removes the trailing coma.
sentence = sentence.substr(0,sentence.length-2)+".";
// I have 2 apples, 5 oranges, 1 pear.