Console

• Theconsole is a panel which displays important messages for developers.
• Calling the.log() method on theconsole object will print or log to the console the data within parenthesis.

The string,Hello!, is being printed to the console.

console.log("Hello!");
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Output:

Hello!

Comments

• Acomment is a useful note within a program.
• It is ignored by the program and exists solely for informational purposes to those reading your code.

Use two forward slashes// for a single-line comment.Use/* at the start and*/ at the end of a multi-line comment.

Single-line comment:

//Hey! I'm ignored by the program.
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Multi-line comment:

/*
 Me too!
 This is all commented.
 */
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Data Types

String

• Any grouping of characters surrounded by single'' or double"" quotes

'New York City'
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Number

• Any number including decimals

40.7
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Boolean

• true orfalse values

true
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Null

• The absence of a value

null
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Arithmetic Operators

• Addition: +

• Subtraction: -

• Multiplication: *

• Division: /

• Remainder (modulo): %

  • Returns the remainder of dividing the right-hand number by the left-hand number.

console.log(5+7);
console.log(6-2);
console.log(3*5);
console.log(10/5);
console.log(22%7);
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Output:

1241525

String Concatenation

• String concatenation is the process of appending one string to another.
• Using the+ operator on two strings, we can append the string on the right to the string on the left.

console.log('New '+'York');
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Output:

New York

Properties

• Aproperty is stored information about an instance of a data type.
• To utilize a property, append an instance with a period followed by the property name.

Appending thelength property on the instance of a string returns the number of characters in that string.

console.log("Codecademy".length);
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Output:

10

Methods

• Methods are actions that can be performed on an instance of a data type.
• To utilize a method, append an instance with a period, (the. operator), the method name, and opening and closing parentheses.

Calling the.toUpperCase()method on the string instance returns the string in all capital letters.

console.log('codecademy'.toUpperCase());
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Output:

CODECADEMY

Built-in Objects

• Built-in objects are collections of methods and properties provided byJavaScript.

Calling the.ceil() method on the built-inMath object returns the next whole number rounded up.

console.log(Math.ceil(43.8));
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Output:

44

'The Codecademy Team, composed of experienced educators and tech experts, is dedicated to making tech skills accessible to all. We empower learners worldwide with expert-reviewed content that develops and enhances the technical skills needed to advance and succeed in their careers.'