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Introduction to JavaScript
course content

Contenuti del Corso

Introduction to JavaScript

Introduction to JavaScript

1. Getting Started
First Javascript Console ApplicationChallenge: Showing some OutputChallenge: Outputing Multiple LinesDealing with NumbersChallenge: Working with NumbersChallenge: Calculating the Speed of a CarChallenge: Calculating Area of a TrapeziumOutputting Multiple ValuesChallenge: Consoling Meaningful OutputHow to Use Comments in Javascript?Challenge: Adding a CommentMulti-Line CommentsChallenge: Commenting out CodeWhat Is JavaScript anyway?
2. Manipulating Data
Storing DataChallenge: Declaring a VariableChallenge: Accessing Data From a VariableChallenge: Fixing Variable NamesChallenge: Reassigning a VariableConstantsChallenge: Declaring & Using ConstantsPerforming Arithmetic On VariablesChallenge: Making a Salary CalculatorChallenge: Adjusting Salary with a BonusExploring Primitive Data TypesChallenge: Declaring a Boolean ValueHow different Data Types InteractChallenge: Concatenating StringsChallenge: Creating User Profile & Activity Details
3. Conditional Statements
Comparison OperatorsChallenge: Checking Age EligibilityThe `if` StatementChallenge: Weather-Based Outfit RecommenderChallenge: Even or OddNested Conditional StatementsThe `else` ClauseChallenge: Improving Even or Odd CheckerChallenge: Temperature AdvisorThe `else if` ClauseChallenge: Grade Categorizer` AND` Logical OperatorChallenge: Checking if a Number is Even and PositiveOR Logical OperatorChallenge: Accessing Control System
4. Mastering Functions
What Are Functions?Challenge: Simple FunctionChallenge: Calculating the Speed of a CarScopesPassing Data into FunctionsChallenge: Fixing the Speed FunctionChallenge: Improving the Grade CategorizerTask: Defining a Compound FunctionReturning Data from FunctionsDefault ValuesChallenge: Email Auto-Responder with Default Parameters
5. Exploring Arrays
What Are Arrays?Challenge: Defining An ArrayChallenge: IndexingAdding Values to an ArrayChallenge: Pushing Elements to an ArrayRemoving Elements from an ArrayChallenge: Practicing `pop` & `shift`The `length` PropertyChallenge: Counting ElementsThe `includes` MethodChallenge: Searching for Animals in the Zoo
6. Discovering Loops
The `for` LoopTask: Printing a SequenceThe `while` LoopChallenge: Printing Fibonacci SequenceThe `do-while` LoopChallenge: Random Multiple of 7Using Loops with ArraysChallenge: Finding the Average Price of ItemsSummary

book
Scopes

Note
Definition

A Scope is simply an area in the code where a variable can be accessed or used.

There are two types of scopes:

  1. Global Scope;

  2. Local Scope.

If a variable is defined inside a block of code (between curly brackets {}), it is said to have a local scope. This means that it can only be accessed from inside that function or code block, or any nested blocks:


              
123456789101112

            
function exampleFunc() {
  let exampleVariable = 10;

  console.log(exampleVariable); // Valid

  if(10 + 10 == 20) {
    console.log(exampleVariable); // Valid
  }
}

exampleFunc();
console.log(exampleVariable); // Shows error
copy

A variable that is defined outside of any code block is said to have a Global Scope, and it can be accessed from anywhere:


              
123456789101112

            
let exampleVariable = 10;

function exampleFunc() {
  console.log(exampleVariable); // Valid

  if(10 + 10 == 20) {
    console.log(exampleVariable); // Valid
  }
}

exampleFunc();
console.log(exampleVariable); // Valid
copy

A variable defined in a lower (nested) scope cannot be accessed from a higher (parent) scope:


              
1234567891011

            
function exampleFunc() {
  if(10 + 10 == 20) {
    let exampleVariable = 10;
    console.log(exampleVariable); // Valid
  }

  console.log(exampleVariable); // Shows error
}

exampleFunc();
console.log(exampleVariable); // Shows error
copy
question mark

Which of the following statements about variable scope is true?

Select the correct answer

Tutto è chiaro?

Come possiamo migliorarlo?

Grazie per i tuoi commenti!

Sezione 4. Capitolo 4

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course content

Contenuti del Corso

Introduction to JavaScript

Introduction to JavaScript

1. Getting Started
First Javascript Console ApplicationChallenge: Showing some OutputChallenge: Outputing Multiple LinesDealing with NumbersChallenge: Working with NumbersChallenge: Calculating the Speed of a CarChallenge: Calculating Area of a TrapeziumOutputting Multiple ValuesChallenge: Consoling Meaningful OutputHow to Use Comments in Javascript?Challenge: Adding a CommentMulti-Line CommentsChallenge: Commenting out CodeWhat Is JavaScript anyway?
2. Manipulating Data
Storing DataChallenge: Declaring a VariableChallenge: Accessing Data From a VariableChallenge: Fixing Variable NamesChallenge: Reassigning a VariableConstantsChallenge: Declaring & Using ConstantsPerforming Arithmetic On VariablesChallenge: Making a Salary CalculatorChallenge: Adjusting Salary with a BonusExploring Primitive Data TypesChallenge: Declaring a Boolean ValueHow different Data Types InteractChallenge: Concatenating StringsChallenge: Creating User Profile & Activity Details
3. Conditional Statements
Comparison OperatorsChallenge: Checking Age EligibilityThe `if` StatementChallenge: Weather-Based Outfit RecommenderChallenge: Even or OddNested Conditional StatementsThe `else` ClauseChallenge: Improving Even or Odd CheckerChallenge: Temperature AdvisorThe `else if` ClauseChallenge: Grade Categorizer` AND` Logical OperatorChallenge: Checking if a Number is Even and PositiveOR Logical OperatorChallenge: Accessing Control System
4. Mastering Functions
What Are Functions?Challenge: Simple FunctionChallenge: Calculating the Speed of a CarScopesPassing Data into FunctionsChallenge: Fixing the Speed FunctionChallenge: Improving the Grade CategorizerTask: Defining a Compound FunctionReturning Data from FunctionsDefault ValuesChallenge: Email Auto-Responder with Default Parameters
5. Exploring Arrays
What Are Arrays?Challenge: Defining An ArrayChallenge: IndexingAdding Values to an ArrayChallenge: Pushing Elements to an ArrayRemoving Elements from an ArrayChallenge: Practicing `pop` & `shift`The `length` PropertyChallenge: Counting ElementsThe `includes` MethodChallenge: Searching for Animals in the Zoo
6. Discovering Loops
The `for` LoopTask: Printing a SequenceThe `while` LoopChallenge: Printing Fibonacci SequenceThe `do-while` LoopChallenge: Random Multiple of 7Using Loops with ArraysChallenge: Finding the Average Price of ItemsSummary

book
Scopes

Note
Definition

A Scope is simply an area in the code where a variable can be accessed or used.

There are two types of scopes:

  1. Global Scope;

  2. Local Scope.

If a variable is defined inside a block of code (between curly brackets {}), it is said to have a local scope. This means that it can only be accessed from inside that function or code block, or any nested blocks:


              
123456789101112

            
function exampleFunc() {
  let exampleVariable = 10;

  console.log(exampleVariable); // Valid

  if(10 + 10 == 20) {
    console.log(exampleVariable); // Valid
  }
}

exampleFunc();
console.log(exampleVariable); // Shows error
copy

A variable that is defined outside of any code block is said to have a Global Scope, and it can be accessed from anywhere:


              
123456789101112

            
let exampleVariable = 10;

function exampleFunc() {
  console.log(exampleVariable); // Valid

  if(10 + 10 == 20) {
    console.log(exampleVariable); // Valid
  }
}

exampleFunc();
console.log(exampleVariable); // Valid
copy

A variable defined in a lower (nested) scope cannot be accessed from a higher (parent) scope:


              
1234567891011

            
function exampleFunc() {
  if(10 + 10 == 20) {
    let exampleVariable = 10;
    console.log(exampleVariable); // Valid
  }

  console.log(exampleVariable); // Shows error
}

exampleFunc();
console.log(exampleVariable); // Shows error
copy
question mark

Which of the following statements about variable scope is true?

Select the correct answer

Tutto è chiaro?

Come possiamo migliorarlo?

Grazie per i tuoi commenti!

Sezione 4. Capitolo 4
Siamo spiacenti che qualcosa sia andato storto. Cosa è successo?
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