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

Anthony Truby
Anthony Truby
2,840 Points
Posted by Anthony Truby
Anthony Truby
2,840 Points

'for in' loop task. global property forbidden?

What am i doing wrong here? I thought i was doing exactly what was just described to me, but no matter what i change 'prop' to, e.g. cace, it comes up with error about strict mode and the global property 'prop' or 'cace'? Thanks

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>
Anthony Truby
Anthony Truby
2,840 Points
Anthony Truby
Anthony Truby
2,840 Points

I changed 'prop' to 'fshss'....

Bummer: There was an error with your code: ReferenceError: Strict mode forbids implicit creation of global property 'fshss'

Surely 'fshss' isn't a global property? what am i missing? ha

1 Answer

Steven Parker
Steven Parker
210,424 Points
Steven Parker
Steven Parker
210,424 Points

You need to use "var" or "let" to explicitly declare the loop variable:

for (let prop in shanghai) {

If you don't declare a loop variable, it is implicitly global.

Anthony Truby
Anthony Truby
2,840 Points
Anthony Truby
Anthony Truby
2,840 Points

Knew it would be something simple, thanks man!