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31 lines
1006 B
Markdown
31 lines
1006 B
Markdown
# for...in Iterates Over Object Properties
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I don't reach for _for loops_ very often, so when I needed one recently I
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thought I'd check out the newer `for...in` construct. It didn't behave quite
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how I was expecting. I thought it would iterate over the values in the
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target list, instead it seemed to be iterating over the indices.
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The [MDN
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docs](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Statements/for...in)
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explain what is going on:
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> The `for...in` statement iterates over all non-Symbol, enumerable properties
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> of an object.
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An array is an object whose properties are the indices of the values stored
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in the array.
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```javascript
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const fruits = ["apple", "banana", "orange"];
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for (let fruit in fruits) {
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console.log(fruit, fruits[fruit]);
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}
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// => "0" "apple"
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// => "1" "banana"
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// => "2" "orange"
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```
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The iteration value wasn't what I was looking for, but in this case I can
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use it to access the value from the list. I'd be better off using a standard
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_for loop_ though.
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