What if . . . 🤔 I nested the `i` assignment inside another function. Why on earth does this work as a solution!?

const courses = [
  'Introducing JavaScript',
  'JavaScript Basics',
  'JavaScript Loops, Arrays and Objects',
  'Getting Started with ES2015',
  'JavaScript and the DOM',
  'DOM Scripting By Example'
];



function addNewTeachers(newTeachers) {
  i = courses.length; // ❓ I moved `i` here from the global scope but I NEVER DECLARED IT
  newTeachers.forEach((newTeacher) => {
    teachers.push({name: newTeacher.name, topicArea: newTeacher.topicArea});
  });
}
addNewTeachers(newTeachers)



function printTreehouseSummary() {
  for (let i = 0; i < teachers.length; i++) {
     console.log(`${teachers[i].name} teaches ${teachers[i].topicArea}`);
    }
  console.log(`Treehouse has ${i} JavaScript courses, and ${teachers.length} Javascript teachers`);
  // ❓How on earth does it have access the correct value (6) here??
}


printTreehouseSummary();