From e8d7d60f0b05c80fe755adbc3bacace3b900ea34 Mon Sep 17 00:00:00 2001 From: c0d1ng_ma5ter Date: Mon, 10 Feb 2025 16:56:30 -0600 Subject: [PATCH] fix(curriculum): Update JavaScript Variables and Data Types Review (#58679) Co-authored-by: Jessica Wilkins <67210629+jdwilkin4@users.noreply.github.com> --- .../6723be264695fb7e619fe1fa.md | 44 +++++++++---------- 1 file changed, 22 insertions(+), 22 deletions(-) diff --git a/curriculum/challenges/english/25-front-end-development/review-javascript-variables-and-data-types/6723be264695fb7e619fe1fa.md b/curriculum/challenges/english/25-front-end-development/review-javascript-variables-and-data-types/6723be264695fb7e619fe1fa.md index c9329ee6cea..0f05fa68aaa 100644 --- a/curriculum/challenges/english/25-front-end-development/review-javascript-variables-and-data-types/6723be264695fb7e619fe1fa.md +++ b/curriculum/challenges/english/25-front-end-development/review-javascript-variables-and-data-types/6723be264695fb7e619fe1fa.md @@ -21,16 +21,16 @@ Data types help the program understand the kind of data it's working with, wheth - **Floating point**: A floating point number is a number with a decimal point. Examples include 3.14, 0.5, and 0.0001. - **String**: A string is a sequence of characters, or text, enclosed in quotes. `"I like coding"` and `'JavaScript is fun'` are examples of strings. - **Boolean**: A boolean represents one of two possible values: `true` or `false`. You can use a boolean to represent a condition, such as `isLoggedin = true`. -- **Undefined and Null**: An undefined value is a variable that has been declared but not assigned a value. A null value is an empty value, or a variable that has intentionally been assigned a value of `null`. +- **Undefined and Null**: An `undefined` value is a variable that has been declared but not assigned a value. A `null` value is an empty value, or a variable that has intentionally been assigned a value of `null`. - **Object**: An object is a collection of key-value pairs. The key is the property name, and the value is the property value. Here, the `pet` object has three properties or keys: `name`, `age`, and `type`. The values are `Fluffy`, `3`, and `dog`, respectively. ```js let pet = { - name: 'Fluffy', + name: "Fluffy", age: 3, - type: 'dog' + type: "dog" }; ``` @@ -39,8 +39,8 @@ let pet = { In this example below, two symbols are created with the same description, but they are not equal. ```js -const crypticKey1= Symbol('saltNpepper'); -const crypticKey2= Symbol('saltNpepper'); +const crypticKey1= Symbol("saltNpepper"); +const crypticKey2= Symbol("saltNpepper"); console.log(crypticKey1 === crypticKey2); // false ``` @@ -63,21 +63,21 @@ let cityName; - To assign a value to a variable, you can use the assignment operator `=`. ```js -cityName = 'New York'; +cityName = "New York"; ``` - Variables declared using `let` can be reassigned a new value. ```js -cityName = 'Los Angeles'; +cityName = "Los Angeles"; console.log(cityName); // Los Angeles ``` - Apart from `let`, you can also use `const` to declare a variable. However, a `const` variable cannot be reassigned a new value. ```js -const cityName = 'New York'; -cityName = 'Los Angeles'; // TypeError: Assignment to constant variable. +const cityName = "New York"; +cityName = "Los Angeles"; // TypeError: Assignment to constant variable. ``` - Variables declared using `const` find uses in declaring constants, that are not allowed to change throughout the code, such as `PI` or `MAX_SIZE`. @@ -103,8 +103,8 @@ let alsoCorrect = "This is also a string"; - Strings are immutable in JavaScript. This means that once a string is created, you cannot change the characters in the string. However, you can still reassign strings to a new value. ```js -let firstName = 'John'; -firstName = 'Jane'; // Reassigning the string to a new value +let firstName = "John"; +firstName = "Jane"; // Reassigning the string to a new value ``` ## String Concatenation in JavaScript @@ -112,26 +112,26 @@ firstName = 'Jane'; // Reassigning the string to a new value - Concatenation is the process of joining multiple strings or combining strings with variables that hold text. The `+` operator is one of the simplest and most frequently used methods to concatenate strings. ```js -let studentName = 'Asad'; +let studentName = "Asad"; let studentAge = 25; -let studentInfo = studentName + ' is ' + studentAge + ' years old.'; +let studentInfo = studentName + " is " + studentAge + " years old."; console.log(studentInfo); // Asad is 25 years old. ``` - If you need to add or append to an existing string, then you can use the `+=` operator. This is helpful when you want to build upon a string by adding more text to it over time. ```js -let message = 'Welcome to programming, '; -message += 'Asad!'; +let message = "Welcome to programming, "; +message += "Asad!"; console.log(message); // Welcome to programming, Asad! ``` -- Another way you can concatenate strings is to use the concat method. This method joins two or more strings together. +- Another way you can concatenate strings is to use the `concat()` method. This method joins two or more strings together. ```js -let firstName = 'John'; -let lastName = 'Doe'; -let fullName = firstName.concat(' ', lastName); +let firstName = "John"; +let lastName = "Doe"; +let fullName = firstName.concat(" ", lastName); console.log(fullName); // John Doe ``` @@ -140,7 +140,7 @@ console.log(fullName); // John Doe - The `console.log()` method is used to log messages to the console. It's a helpful tool for debugging and testing your code. ```js -console.log('Hello, World!'); +console.log("Hello, World!"); // Output: Hello, World! ``` @@ -149,7 +149,7 @@ console.log('Hello, World!'); - Semicolons are primarily used to mark the end of a statement. This helps the JavaScript engine understand the separation of individual instructions, which is crucial for correct execution. ```js -let message = 'Hello, World!'; // first statement ends here +let message = "Hello, World!"; // first statement ends here let number = 42; // second statement starts here ``` @@ -201,7 +201,7 @@ let isLoggedin = true; console.log(typeof isLoggedin); // boolean ``` -- However, there's a well-known quirk in JavaScript when it comes to null. The `typeof` operator returns `object` for null values. +- However, there's a well-known quirk in JavaScript when it comes to `null`. The `typeof` operator returns `object` for `null` values. ```js let user = null;