Using Objects in For Of Loops

Question

Why isn\'t is possible to use objects in for of loops? Or is this a browser bug? This code doesn\'t work in Chrome 42, saying undefined is not a function:

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Answer 1

Object literals don't have built-in iterators, which are required to work with for...of loops. However, if you don't want to go thru the trouble of adding your own [Symbol.iterator] to your object, you can simply use the Object.keys() method. This method returns an Array object, which already has a built-in iterator, so you can use it with a for...of loop like this:

const myObject = {
    country: "Canada",
    province: "Quebec",
    city: "Montreal"
}

for (let i of Object.keys(myObject)) {
    console.log("Key:", i, "| Value:", myObject[i]);
}

//Key: country | Value: Canada
//Key: province | Value: Quebec
//Key: city | Value: Montreal