Error about using var
In the same way, for the same purpose, we may use
varbut it has undesirable properties; e.g., its declarations are in the global scope and no error is raised usingvar x = ⋯ifxis already declared.
This is at the end of the Types section. First bullet point of three.
The part that says "its declarations are in the global scope" is incorrect.
Later, in the Scope and Statements section, you say...
let,constdeclare local bindings;varalways makes global ones!
Which again is incorrect. You can try this...
function f() {
var x = 1;
}
console.log(x); // => Uncaught ReferenceError: x is not defined
...and see that x is not defined in the global scope. It will be local to the f function.
The difference about var and let in what regards scope is:
varbindings reach either function scope or the global scope.letbindings can also be limited to block scope.vardeclarations are hoisted to the start of the scope.letbindings are not (*)
(*) To be more precise they are but have a mechanism that prevents usage before declaration and will throw an error, while var won't.