Travis build: 1516

README.md

@@ -1725,8 +1725,8 @@ const join = (arr, separator = ',', end = separator) =>
       i === arr.length - 2
         ? acc + val + end
         : i === arr.length - 1
-        ? acc + val
-        : acc + val + separator,
+          ? acc + val
+          : acc + val + separator,
     ''
   );
 ```
@@ -4274,10 +4274,10 @@ const getMeridiemSuffixOfInteger = num =>
   num === 0 || num === 24
     ? 12 + 'am'
     : num === 12
-    ? 12 + 'pm'
-    : num < 12
-    ? (num % 12) + 'am'
-    : (num % 12) + 'pm';
+      ? 12 + 'pm'
+      : num < 12
+        ? (num % 12) + 'am'
+        : (num % 12) + 'pm';
 ```
 
 <details>
@@ -5489,11 +5489,11 @@ Throws an exception if `n` is a negative number.
 const factorial = n =>
   n < 0
     ? (() => {
-        throw new TypeError('Negative numbers are not allowed!');
-      })()
+      throw new TypeError('Negative numbers are not allowed!');
+    })()
     : n <= 1
-    ? 1
-    : n * factorial(n - 1);
+      ? 1
+      : n * factorial(n - 1);
 ```
 
 <details>
@@ -6704,8 +6704,8 @@ const deepClone = obj => {
   return Array.isArray(obj) && obj.length
     ? (clone.length = obj.length) && Array.from(clone)
     : Array.isArray(obj)
-    ? Array.from(obj)
-    : clone;
+      ? Array.from(obj)
+      : clone;
 };
 ```
 
@@ -6793,13 +6793,13 @@ const deepMapKeys = (obj, f) =>
   Array.isArray(obj)
     ? obj.map(val => deepMapKeys(val, f))
     : typeof obj === 'object'
-    ? Object.keys(obj).reduce((acc, current) => {
+      ? Object.keys(obj).reduce((acc, current) => {
         const val = obj[current];
         acc[f(current)] =
           val !== null && typeof val === 'object' ? deepMapKeys(val, f) : (acc[f(current)] = val);
         return acc;
       }, {})
-    : obj;
+      : obj;
 ```
 
 <details>
@@ -6870,9 +6870,9 @@ const dig = (obj, target) =>
   target in obj
     ? obj[target]
     : Object.values(obj).reduce((acc, val) => {
-        if (acc !== undefined) return acc;
-        if (typeof val === 'object') return dig(val, target);
-      }, undefined);
+      if (acc !== undefined) return acc;
+      if (typeof val === 'object') return dig(val, target);
+    }, undefined);
 ```
 
 <details>
@@ -7120,17 +7120,19 @@ get(obj, 'selector.to.val', 'target[0]', 'target[2].a'); // ['val to select', 1,
 
 Returns `true` if the target value exists in a JSON object, `false` otherwise.
 
-Check if the key contains `.`, use `String.prototype.split('.')[0]` to get the first part and store as `_key`.
-Use `typeof` to check if the contents of `obj[key]` are an `object` and, if so, call `hasKey` with that object and the remainder of the `key`.
-Otherwise, use `Object.keys(obj)` in combination with `Array.prototype.includes()` to check if the given `key` exists.
+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, key) => {
-  if (key.includes('.')) {
-    let _key = key.split('.')[0];
-    if (typeof obj[_key] === 'object') return hasKey(obj[_key], key.slice(key.indexOf('.') + 1));
-  }
-  return Object.keys(obj).includes(key);
+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;
+  });
 };
 ```
 
@@ -7141,14 +7143,15 @@ const hasKey = (obj, key) => {
 let obj = {
   a: 1,
   b: { c: 4 },
-  'd.e': 5
+  'b.d': 5
 };
-hasKey(obj, 'a'); // true
-hasKey(obj, 'b'); // true
-hasKey(obj, 'b.c'); // true
-hasKey(obj, 'd.e'); // true
-hasKey(obj, 'd'); // false
-hasKey(obj, 'f'); // false
+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
 ```
 </details>
 
@@ -9380,10 +9383,10 @@ Return the `queryString` or an empty string when the `queryParameters` are falsy
 const objectToQueryString = queryParameters => {
   return queryParameters
     ? Object.entries(queryParameters).reduce((queryString, [key, val], index) => {
-      const symbol = index === 0 ? '?' : '&';
-      queryString += (typeof val === 'string') ? `${symbol}${key}=${val}` : '';
-      return queryString;
-    }, '')
+        const symbol = index === 0 ? '?' : '&';
+        queryString += typeof val === 'string' ? `${symbol}${key}=${val}` : '';
+        return queryString;
+      }, '')
     : '';
 };
 ```
@@ -9392,7 +9395,7 @@ const objectToQueryString = queryParameters => {
 <summary>Examples</summary>
 
 ```js
-objectToQueryString({page: '1', size: '2kg', key: undefined}); // '?page=1&size=2kg'
+objectToQueryString({ page: '1', size: '2kg', key: undefined }); // '?page=1&size=2kg'
 ```
 </details>