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

JavaScript Loops, Arrays, and Objects - For In Loop Challenge Task 1 of 2

This challenge's instructions are "Use a for in loop to log each of the property names of the shanghai object to the console."

My code was:

var shanghai = {
  population: 14.35e6,
  longitude: '31.2000 N',
  latitude: '121.5000 E',
  country: 'CHN'

for (prop in shanghai) {
  console.log(prop, ': ', shanghai[prop]);

and I received this error code:

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

What am I missing here? Thanks in advance for your help.

3 Answers

Asif Ulfat
Asif Ulfat
8,610 Points

Hi Anna,

This should help for task 1:

for (var prop in shanghai) { console.log(prop);


The prop variable isn't declared yet.

It wasn't declared in the video example either...he just started using it