update groupBy post

posts/162-array-group-by/index.md

@@ -1,6 +1,6 @@
 ---
-title: "Array Grouping in JavaScript: array.groupBy()"
-description: "array.groupBy() and array.groupByToMap() methods let you group an array by certain criteria."  
+title: "Array Grouping in JavaScript: Object.groupBy()"
+description: "Object.groupBy() and Object.groupByToMap() methods let you group an array by certain criteria."  
 published: "2021-12-20"
 modified: "2023-01-28"
 thumbnail: "./images/cover.png"
@@ -14,13 +14,13 @@ Many developers appreciate Ruby programming language because of the rich standar
 JavaScript also enriches its standard library on strings and arrays step by step. For example, in a previous post, I described
 the new [array.at()](/javascript-array-at/) method.  
 
-Today's hero is the new [array group proposal](https://github.com/tc39/proposal-array-grouping) (currently at stage 3) that introduces new methods `array.groupBy()` and `array.groupByToMap()`. Their [polyfills](https://github.com/zloirock/core-js#array-grouping) are available in `core-js` library.  
+Today's hero is the new [array group proposal](https://github.com/tc39/proposal-array-grouping) (currently at stage 3) that introduces new methods `Object.groupBy()` and `Map.groupBy()`. Their [polyfills](https://github.com/zloirock/core-js#array-grouping) are available in `core-js` library.  
 
 Let's see how you may benefit from the grouping methods.  
 
 <Affiliate />
 
-## 1. array.groupBy()
+## 1. Object.groupBy()
 
 You have a list of products, where each product is an object having 2 properties: `name` and `category`.  
 
@@ -77,12 +77,12 @@ console.log(groupByCategory);
 
 While I do consider `array.reduce()` method useful and powerful, sometimes its readability is not the best.  
 
-Because grouping data is an often occurring task ([recall](https://www.programiz.com/sql/group-by) `GROUP BY` from SQL?) the [array group proposal](https://github.com/tc39/proposal-array-grouping) introduces two useful methods: `array.groupBy()` and `array.groupByToMap()`.  
+Because grouping data is an often occurring task ([recall](https://www.programiz.com/sql/group-by) `GROUP BY` from SQL?) the [array group proposal](https://github.com/tc39/proposal-array-grouping) introduces two useful methods: `Object.groupBy()` and `Map.groupBy()`.  
 
-Here's how to use `array.groupBy()` to create the same grouping by category:
+Here's how to use `Object.groupBy()` to create the same grouping by category:
 
 ```javascript
-const groupByCategory = products.groupBy(product => {
+const groupByCategory = Object.groupBy(products, product => {
   return product.category;
 });
 
@@ -98,33 +98,31 @@ console.log(groupByCategory);
 // }
 ```
 
-[Open the demo.](https://codesandbox.io/s/bold-goodall-r3c4c?file=/src/index.js)
-
-`products.groupBy(product => {...})` returns an object where properties are category names and values are arrays of category products.
+`Object.groupBy(products, product => {...})` returns an object where properties are category names and values are arrays of category products.
 
 Grouping using `products.groupBy()` requires less code and is easier to understand than using `product.reduce()`.  
 
-`array.groupBy(callback)` accepts a callback function that's invoked with 3 arguments: the current array item, the index, and the array itself. The `callback` should return a string: the group name where you'd like to add the item.  
+`Object.groupBy(array, callback)` accepts a callback function that's invoked with 3 arguments: the current array item, the index, and the array itself. The `callback` should return a string: the group name where you'd like to add the item.  
 
 ```javascript
-const groupedObject = array.groupBy((item, index, array) => {
+const groupedObject = Object.groupBy(array, (item, index, array) => {
   // ...
   return groupNameAsString;
 });
 ```
 
-## 2. array.groupByToMap()
+## 2. Map.groupBy()
 
 [Sometimes](/maps-vs-plain-objects-javascript/) you may want to use a `Map` instead of a plain object. The benefit of `Map` is that it accepts any data type as a key, but the plain object is limited to strings and symbols only.  
 
-So, if you'd like to group data into a `Map`, you can use the method `array.groupByToMap()`. 
+So, if you'd like to group data into a `Map`, you can use the method `Map.groupBy()`. 
 
-`array.groupByToMap(callback)` works the same way as `array.groupBy(callback)`, only that it groups items into a `Map` instead of a plain JavaScript object.  
+`Map.groupBy(array, callback)` works the same way as `Object.groupBy(array, callback)`, only that it groups items into a `Map` instead of a plain JavaScript object.  
 
 For example, grouping the products array into a map by category name is performed as follows:
 
 ```javascript
-const groupByCategory = products.groupByToMap(product => {
+const groupByCategory = Map.groupBy(products, product => {
   return product.category;
 });
 
@@ -140,14 +138,12 @@ console.log(groupByCategory);
 // ])
 ```
 
-[Open the demo.](https://codesandbox.io/s/sparkling-waterfall-kdlpy?file=/src/index.js)
-
 ## 3. Conclusion
 
-If you want to easily group the items of an array (similarly to `GROUP BY` in SQL), then welcome the new methods `array.groupBy()` and `array.groupByToMap()`.  
+If you want to easily group the items of an array (similarly to `GROUP BY` in SQL), then welcome the new methods `Object.groupBy()` and `Map.groupBy()`.  
 
 Both functions accept a callback that should return the key of the group where the current items must be inserted.  
 
-`array.groupBy()` groups the items into a plain JavaScript object, while `array.groupByToMap()` groups them into a `Map` instance.  
+`Object.groupBy()` groups the items into a plain JavaScript object, while `Map.groupBy()` groups them into a `Map` instance.  
 
 If you'd like to use these functions right away, then use the [polyfill](https://github.com/zloirock/core-js#array-grouping) provided by core-js library.