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JavaScript JavaScript Loops, Arrays and Objects Tracking Data Using Objects Accessing All of the Properties in an Object

Posted by Henry Powell
Henry Powell
3,426 Points

Trouble with for in loop

Bummer: There was an error with your code: ReferenceError: Strict mode forbids implicit creation of global property 'prop'
script.js

var shanghai = { population: 14.35e6, longitude: '31.2000 N', latitude: '121.5000 E', country: 'CHN' }; for (prop in shanghai) { console.log(prop); }

script.js 
var shanghai = {
  population: 14.35e6,
  longitude: '31.2000 N',
  latitude: '121.5000 E',
  country: 'CHN'
};
for (prop in shanghai) {
  console.log(prop);
}
index.html 
<!DOCTYPE html>
<html>
<head>
  <meta charset="utf-8">
  <title>JavaScript Objects</title>
</head>
<body>
<script src="script.js"></script>
</body>
</html>

2 Answers

Greg Heffley
Greg Heffley
6,371 Points
Greg Heffley
Greg Heffley
6,371 Points

You need to assign prop as a variable.

for (const prop in shanghai) {
  console.log(prop);
}
Henry Powell
Henry Powell
3,426 Points
Henry Powell
Henry Powell
3,426 Points

Thanks Greg!