freeCodeCamp/curriculum/challenges/english/02-javascript-algorithms-and-data-structures/basic-javascript/local-scope-and-functions.english.md

id, title, challengeType, videoUrl, forumTopicId

id	title	challengeType	videoUrl	forumTopicId
56533eb9ac21ba0edf2244bf	Local Scope and Functions	1	https://scrimba.com/c/cd62NhM	18227

Description

Variables which are declared within a function, as well as the function parameters have local scope. That means, they are only visible within that function. Here is a function myTest with a local variable called loc.

function myTest() {
  var loc = "foo";
  console.log(loc);
}
myTest(); // logs "foo"
console.log(loc); // loc is not defined

loc is not defined outside of the function.

Instructions

The editor has two console.logs to help you see what is happening. Check the console as you code to see how it changes. Declare a local variable myVar inside myLocalScope and run the tests.

Note: The console will still have 'ReferenceError: myVar is not defined', but this will not cause the tests to fail.

Tests

tests:
  - text: The code should not contain a global <code>myVar</code> variable.
    testString: |
      function declared(){
        myVar;
      }
      assert.throws(declared, ReferenceError);
  - text: You should add a local <code>myVar</code> variable.
    testString: assert(/functionmyLocalScope\(\)\{.+(var|let|const)myVar.*}/s.test(code.replace(/\s/g, '')));

Challenge Seed

function myLocalScope() {
  'use strict';

  // Only change code below this line

  console.log('inside myLocalScope', myVar);
}
myLocalScope();

// Run and check the console
// myVar is not defined outside of myLocalScope
console.log('outside myLocalScope', myVar);

Solution

function myLocalScope() {
  'use strict';

  // Only change code below this line
  var myVar;
  console.log('inside myLocalScope', myVar);
}
myLocalScope();

// Run and check the console
// myVar is not defined outside of myLocalScope
console.log('outside myLocalScope', myVar);