complete summary: what data structure to use

Author: Evavic44

Diff for: 09-Data-Structure-Modern-Operators-and-Strings/README.md

@@ -542,3 +542,92 @@ console.log(...question.values());
 ```
 
 # Summary: Which Data Structure to Use
+
+Initially we had two main data structures, Arrays and Objects but we have looked at other data structures introduced to JavaScript from ES6.
+
+It's important to know the pros and cons of all the data structures and which one to use at any given point.
+
+## Sources of Data
+
+There are three main sources of Data,
+
+- The Program: Data written directly in source code (E.g: Status Message)
+- From the UI: Data input from the user or Data written in DOM (E.g tasks in a todo app).
+- From External Sources: Data fetched for example from Web API (E.g recipe, objects)
+
+## Data Structures to Use
+
+- Simple List: Arrays or Sets
+- Key/Value Pairs: Objects or Maps
+
+The most common source of Data is the Web API which commonly comes in a `JSON` format and for storing such data, arrays is usually the way to go.
+
+Now there are other data structures not built into JavaScript like:
+
+### Other Built-In
+
+- WeakMap
+- WeakSet
+
+### Non-Built In
+
+- Stacks
+- Queues
+- Linked Lists
+- Trees
+- Hash Tables
+
+## Arrays vs Sets & Objects vs Maps
+
+## Arrays
+
+```js
+const tasks = ["Code", "Eat", "Code"];
+// ["Code", "Eat", "Code"]
+```
+
+1. Use arrays when you need **ordered** list of values(with duplicates).
+2. Use arrays when you need to **manipulate** data
+
+## Sets
+
+```js
+const task = new Set(["Code", "Eat", "Code"]);
+// ["Code", "Eat"]
+```
+
+1. Use Sets when you need to work with **unique** values.
+2. Use Sets when **high performance** is really important.
+3. Use Sets to **remove duplicates** from arrays.
+
+## Objects
+
+```js
+const task = {
+  task: "code",
+  date: "today",
+  repeat: true,
+};
+```
+
+1. More traditional key/value store
+2. Eaiser to write and access values with `.` and `[]` notations
+3. Use when you need to include `functions` (methods)
+4. Use when working with `JSON` (can covert to `Map`)
+
+## Maps
+
+```js
+const task = new Map([
+  ["task", "code"],
+  ["date", "today"],
+  [false, "start coding!"],
+]);
+```
+
+1. Better performance
+2. Keys can have any data type
+3. Easy to iterate
+4. Easy to compute size
+5. Use when you simply need to map key to values
+6. Use when you need keys that are not strings.

Diff for: 09-Data-Structure-Modern-Operators-and-Strings/challenge.js

@@ -215,3 +215,7 @@ for (const player of game.scored) {
   scorers[player] ? scorers[player]++ : (scorers[player] = 1);
 }
 console.log(scorers);
+
+// ----------------------------------------
+// Coding Challenge #3
+// ----------------------------------------

Diff for: 09-Data-Structure-Modern-Operators-and-Strings/script.js

@@ -453,8 +453,6 @@ console.log(rest.get(s));
 rest.set(document.querySelector("h1"), "Heading");
 console.log(rest);
 
-const dat = new Map();
-
 // 🔸Map Iterations🔸
 const question = new Map([
   ["Question", "What is the best programming language in the world?"],
@@ -481,7 +479,8 @@ for (const [key, value] of question) {
   }
 }
 
-const answer = Number(prompt("What is your answer?"));
+// const answer = Number(prompt("What is your answer?"));
+const answer = 3;
 console.log(
   answer === question.get("correct")
     ? `${answer} ${question.get(true)}`

Diff for: README.md

@@ -337,9 +337,14 @@ Welcome to JavaScript Fundamentals part two.
 - [Rest Patterns and Parameters]()
 - [Short Circuting (OR ||)]()
 - [Nullish Coalescing Operator]()
+- [Coding Challenge]()
 - [Looping Arrays (For of Loop)]()
+- [Enhanced Object Literals]()
 - [Optional Chaining]()
 - [Looping Objects, Keys, Values and Entries]()
+- [Coding Challenge 2]()
 - [Sets]()
-- [Maps]()
+- [Maps Fundamentals]()
 - [Maps Iteration]()
+- [Summary: Which Data Structure to Use]()
+- [Coding Challenge 3]()