Rename js snippets

snippets/js/s/object-has-key.md

@@ -0,0 +1,44 @@
+---
+title: Check if object has key
+type: snippet
+language: javascript
+tags: [object]
+author: chalarangelo
+cover: cloudy-mountaintop
+dateModified: 2020-10-19T22:49:51+03:00
+---
+
+Checks if the target value exists in a JSON object.
+
+- Check if `keys` is non-empty and use `Array.prototype.every()` to sequentially check its keys to internal depth of the object, `obj`.
+- Use `Object.prototype.hasOwnProperty()` to check if `obj` does not have the current key or is not an object, stop propagation and return `false`.
+- Otherwise assign the key's value to `obj` to use on the next iteration.
+- Return `false` beforehand if given key list is empty.
+
+```js
+const hasKey = (obj, keys) => {
+  return (
+    keys.length > 0 &&
+    keys.every(key => {
+      if (typeof obj !== 'object' || !obj.hasOwnProperty(key)) return false;
+      obj = obj[key];
+      return true;
+    })
+  );
+};
+```
+
+```js
+let obj = {
+  a: 1,
+  b: { c: 4 },
+  'b.d': 5
+};
+hasKey(obj, ['a']); // true
+hasKey(obj, ['b']); // true
+hasKey(obj, ['b', 'c']); // true
+hasKey(obj, ['b.d']); // true
+hasKey(obj, ['d']); // false
+hasKey(obj, ['c']); // false
+hasKey(obj, ['b', 'f']); // false
+```