Variable declaration

1 
fetch("http://api.openweathermap.org/data/2.5/weather?lat=17.3764&lon=78.5579&units=Imperial&appid=3f7074e9bd977fa42d82638b27b4560b")
.then((response) =>{
	// console.log("text: ",response.json)
	return response.json()
})
.then((data)=>{
	console.log("data:",data.coord)
	var sunrise = data.sys.sunrise
	// console.log(sunrise)
  	var weather = data.weather
    var para = document.querySelector('p')
    for(i in weather){
	para.innerHTML = weather[i].description
    }

	
})
.catch()

console.log(sunrise)

can any one help me why it is giving error as: sunrise is not declared ? my claim is when i declare a varibale as var it should be global. please help me

2

Hello! Welcome to the community :slight_smile:!

When you declare variables with var they are declared at the function scope, not at the global scope (unless you declare it at the top of the file). You could make it global if you remove the var or assign it to the window object directly: window.sunrise = ..., but that’s discouraged.

Nevertheless, it will not work as (I think) you expect, since the console.log will execute before there’s a value assigned to the sunrise variable. When you use a Promise or asynchronous based call, the execution of the script continues regardless, in other words, it doesn’t stop to wait for the result.

1 Like
3

even though i declared sunrise as global it is still not working.
it says undefined

4

Yes, that’s what I meant by this:

When you use a Promise or asynchronous based call, the execution of the script continues regardless, in other words, it doesn’t stop to wait for the result

You have to log the result inside the callback where the variable is initialized (or assigned a value).

You could cheat if you write something like this:

const handle = setTimeout(function() {
  console.log(sunrise);
  clearTimeout(handle);
}, 2000);

Which will wait 2 seconds and then log the value to the console. This is discouraged though, so do it only for testing/learning.

Edit: using a timeout is not guaranteed to work. What I wrote is assuming the call to the API (http://api.openweathermap.org) will resolve the data in less than 2 seconds, so if it takes more than 2 seconds it will still log undefined.