Add unary

snippets/unary.md

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+### unary
+
+Creates a function that accepts up to one argument, ignoring any additional arguments.
+
+Call the provided function, `fn`, with just the first argument given.
+
+```js
+const unary = fn => val => fn(val);
+```
+
+```js
+['6', '8', '10'].map(unary(parseInt)); // [6, 8, 10]
+```