Left expression of function in JavaScript

Let's consider the following code:

javascript+function func() {
  console.log('!');
}

As you already know, this function is a function expression, regardless of the fact that it has a name (we already found out that the presence of a name is not a criterion at all). Remove this plus - and get Function Declaration:

javascriptfunction func() {
  console.log('!');
}

Let's put + on the line above before the function - it will again become a Function Expression:

javascript+
function func() {
  console.log('!');
}

And now after the plus we put the number 1 and a semicolon - our function will become a Function Declaration:

javascript+1;
function func() {
  console.log('!');
}

Why so: because on the first line one complete command is written, closed with a semicolon. Therefore, this command does not affect our function in any way.

In fact, the semicolon can be removed, because in JavaScript it is not required - the function will still remain a Function Declaration:

javascript+1
function func() {
  console.log('!');
}

But if after 1 you put one more plus, then the function will become a Function Expression:

javascript+1+
function func() {
  console.log('!');
}

Why so: because on the first line there is an unfinished expression - there is a plus and nothing after it. Therefore, the JavaScript interpreter thinks that this plus refers to the line below, that is, to our function.

If there is a complete expression on the first line, then JavaScript automatically puts a semicolon on it and this expression does not affect our function in any way.

javascript-
function func() {
  console.log('!');
}

javascript-1;
function func() {
  console.log('!');
}

javascript-1
function func() {
  console.log('!');
}

javascript1
function func() {
  console.log('!');
}

javascript-1-
function func() {
  console.log('!');
}