• var statement is known throughout the function it is defined in, from the start of the function.
• let statement is only known in the block it is defined in, from the moment (...)

First, remove all of the items from the Git Index (not from the working directory or local repo), and afterward refreshes the Git Index, while respecting git ignores.

git
 (...)

Objects in JavaScript can be thought of as maps between keys and values. The delete operator is used to remove these keys.

var obj = {
  myProperty: 1    
}
console.log(obj.hasOwnProperty('myProperty'))
 (...)

The difference is that functionOne is a function expression and so only defined when that line is reached, whereas functionTwo is a function declaration and is defined as soon (...)