René's URL Explorer Experiment

{"@context":"https://schema.org","@type":"DiscussionForumPosting","headline":"[question] Why do many files in the lib directory use `var` sometimes and `let` other times?","articleBody":"\u003c!--\r\nThank you for reporting an issue.\r\n\r\nThis issue tracker is for bugs and issues found within Node.js core.\r\nIf you require more general support please file an issue on our help\r\nrepo. https://github.com/nodejs/help\r\n\r\n\r\nPlease fill in as much of the template below as you're able.\r\n\r\nVersion: output of `node -v`\r\nPlatform: output of `uname -a` (UNIX), or version and 32 or 64-bit (Windows)\r\nSubsystem: if known, please specify affected core module name\r\n\r\nIf possible, please provide code that demonstrates the problem, keeping it as\r\nsimple and free of external dependencies as you are able.\r\n--\u003e\r\n\r\n* **Version**: 12.3.1\r\n\r\n\u003c!-- Enter your issue details below this comment. --\u003e\r\nWhile looking through the node.js source code, I have found quite a few `var` declarations. In the same files I have also found `let` declarations. `let` declarations are almost always considered better, and can always be used in place of `var` declarations. I was thinking about fixing this and creating a PR but wanted to know if there was a specific reason for using `var` sometimes and `let` other times. Scope could be a reason, but could be transformed like this:\r\n\r\n```js\r\nif(/*...*/) {\r\n    var foo = 'bar';\r\n}\r\n\r\n//is the same as\r\nlet foo;\r\nif(/*...*/) {\r\n    foo = 'bar';\r\n}\r\n```\r\n","author":{"url":"https://github.com/MilesZew","@type":"Person","name":"MilesZew"},"datePublished":"2019-06-01T20:32:20.000Z","interactionStatistic":{"@type":"InteractionCounter","interactionType":"https://schema.org/CommentAction","userInteractionCount":2},"url":"https://github.com/28009/node/issues/28009"}