Lexical environment: global and functional

index.js

// Global lexical environment is here
let a = 'a'
const b = 'b'
for (let i = 0; i < 5; i++) {
  console.log(i)
}
function foo() {
  // Functional lexical environment is here
  let a = 'A'
  function bar() {
    // And here is another functional lexical environment
    let b = 'B'
  }
}