René's URL Explorer Experiment

{"@context":"https://schema.org","@type":"DiscussionForumPosting","headline":"Error about using var","articleBody":"\u003e In the same way, for the same purpose, we may use `var` but it has undesirable properties; e.g., its declarations are in the global scope and no error is raised using `var x = ⋯` if `x` is already declared.\r\n\r\nThis is at the end of the _Types_ section. First bullet point of three.\r\n\r\nThe part that says _\"its declarations are in the global scope\"_ is incorrect.\r\n\r\nLater, in the _Scope and Statements_ section, you say...\r\n\r\n\u003e`let`, `const` declare local bindings; `var` always makes global ones!\r\n\r\nWhich again is incorrect. You can try this...\r\n\r\n```javascript\r\nfunction f() {\r\n    var x = 1;\r\n}\r\nconsole.log(x); // =\u003e Uncaught ReferenceError: x is not defined\r\n```\r\n\r\n...and see that `x` is **not** defined in the global scope. It will be local to the `f` function.\r\n\r\nThe difference about `var` and `let` in what regards scope is:\r\n\r\n- `var` bindings reach either _function scope_ or the _global scope_. `let` bindings can also be limited to _block scope_.\r\n- `var` declarations are hoisted to the start of the scope. `let` bindings are not (*)\r\n\r\n(*) To be more precise they are but have a mechanism that prevents usage before declaration and will throw an error, while `var` won't.","author":{"url":"https://github.com/gezeta-id","@type":"Person","name":"gezeta-id"},"datePublished":"2021-01-27T08:38:20.000Z","interactionStatistic":{"@type":"InteractionCounter","interactionType":"https://schema.org/CommentAction","userInteractionCount":0},"url":"https://github.com/1/JavaScriptCheatSheet/issues/1"}