Fix typos in spaces

Fix typo to fit the context

Fix typo add space

Fix small typo

Fix small typo

Fix typo

Fix typo

Fix typo

Fix typo

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Fix typo

Fix typo

Update tail.md

Fix typo

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Fix typo

Fix typo

Fix typo

Fix typo

Fix small typo

Fix typo

Fix small typo

Fix typo

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Fix typo

Fix typo

Fix typo

Fix typo

Fix typo

Fix typo

snippets/pick.md

@@ -2,7 +2,7 @@
 
 Picks the key-value pairs corresponding to the given keys from an object.
 
-Use `Array.reduce()` to convert the filtered/picked keys back to a object with the corresponding key-value pair if the key exist in the obj.
+Use `Array.reduce()` to convert the filtered/picked keys back to an object with the corresponding key-value pair if the key exists in the obj.
 
 ```js
 const pick = (obj, arr) =>