Add Matching A Computed Property In Function Args as a javascript til

javascript/matching-a-computed-property-in-function-args.md

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+# Matching A Computed Property In Function Args
+
+The [computed property name](http://es6-features.org/#ComputedPropertyNames)
+feature of ES6 allows you to reference a variable in object assignments and
+destructurings. This syntax is flexible enough that it can be used in the
+arguments portion of a function declaration. In fact, it can even be matched
+against another argument -- allowing the creation of some handy, yet terse
+functions.
+
+```javascript
+const get = (key, { [key]: foundValue }) => foundValue;
+```
+
+Notice that the first argument, `key`, will match against the computed
+property name in the second argument. The `foundValue` will correspond to
+whatever `key` maps to in the given object.
+
+This `get` function can then be used like so.
+
+```javascript
+const stuff = { a: 1, b: 2, c: 3 };
+
+console.log("Get a:", get("a", stuff)); // 1
+console.log("Get d:", get("d", stuff)); // undefined
+```
+
+h/t
+[@sharifsbeat](https://twitter.com/sharifsbeat/status/1084235020183748610)