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Please enable JavaScript in your browser settings or update your browser.Learn The `includes` Method | Exploring Arrays
Introduction to JavaScript
course content

Course Content

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
The `includes` Method

The includes method can be used to quickly determine of a specific element exists in the array or not.

Following is the general syntax of the includes method:

arrayName.includes(element);

The includes method returns a boolean (true or false) value based on whether or not the element exists in the array.

  • Returns true if the element is found;
  • Returns false if the element is not found.

              
1234

            
let itemsInStock = ["Laptop", "Phone", "Tablet", "Charger"];

console.log(itemsInStock.includes("Phone"));
console.log(itemsInStock.includes("Headphones"));
copy
Note
Note

The includes method performs a strict comparison (===), meaning it checks for exact matches, including case sensitivity. For example, itemsInStock.includes("phone") would return false because "phone" (lowercase) is not the same as "Phone" (uppercase "P").

1. What will be the output of the following code?

2. Which of the following statements is true about the includes method?

question mark

What will be the output of the following code?

Select the correct answer

question mark

Which of the following statements is true about the includes method?

Select the correct answer

Everything was clear?

How can we improve it?

Thanks for your feedback!

SectionΒ 5. ChapterΒ 10

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course content

Course Content

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
The `includes` Method

The includes method can be used to quickly determine of a specific element exists in the array or not.

Following is the general syntax of the includes method:

arrayName.includes(element);

The includes method returns a boolean (true or false) value based on whether or not the element exists in the array.

  • Returns true if the element is found;
  • Returns false if the element is not found.

              
1234

            
let itemsInStock = ["Laptop", "Phone", "Tablet", "Charger"];

console.log(itemsInStock.includes("Phone"));
console.log(itemsInStock.includes("Headphones"));
copy
Note
Note

The includes method performs a strict comparison (===), meaning it checks for exact matches, including case sensitivity. For example, itemsInStock.includes("phone") would return false because "phone" (lowercase) is not the same as "Phone" (uppercase "P").

1. What will be the output of the following code?

2. Which of the following statements is true about the includes method?

question mark

What will be the output of the following code?

Select the correct answer

question mark

Which of the following statements is true about the includes method?

Select the correct answer

Everything was clear?

How can we improve it?

Thanks for your feedback!

SectionΒ 5. ChapterΒ 10
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