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Lesson Notes

Understanding JavaScript Array Properties

Arrays in JavaScript come with built-in properties, like length, to help you inspect and manage them.

Getting the Length

Use the .length property to find how many elements are in an array:

1const myList = [0, null, true, false, { name: "Alice" }]; 2console.log(`The length of the list is: ${myList.length}`); 3// Outputs: The length of the list is: 5

If you remove elements:

1myList.pop(); 2myList.pop(); 3console.log(`The length of the list is: ${myList.length}`); 4// Outputs: The length of the list is: 3

Accessing Properties Directly

You don’t need a variable—access properties right on the array literal:

1console.log([1, 2, 3, "yes"].length); // 4

Key Points

  • .length reflects the highest index + 1.
  • It updates automatically when you add or remove elements.

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Basic Arrays in Javascript
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Array Indexing, Access Elements

Exploring Array Properties

In this lesson, you will learn about JavaScript array properties like `.length`, learning how to easily determine the number of elements in an array.

2m 19s

Course Content

0 of 32 lessons completed
1. Introduction & Setup
0 of 4 completed
1

Setting up VS Code

3m 18s
2

Creating Your First HTML Page with VS Code and AI

1m 8s
3

Creating and Linking Your First JavaScript File in VS Code

3m 56s
4

Understanding the Basic HTML Structure for JavaScript Integration

3m 10s
2. Variables, Data Types, Operators
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1

Variables using the "var" keyword

2m 57s
2

Variables with "const" and "let" keywords

3m 48s
3

Code comments

3m 2s
4

String Interpolation (Template Literals)

2m 26s
5

Block Scope

5m 16s
6

Primitives in Javascript

5m 56s
7

Javascript "null" vs "undefined"

3m 20s
8

Equality Operators in JavaScript

5m 45s
9

Greater Than and Less Than in JavaScript

1m 29s
3. Control Structures ("If", "Else" statements and loops)
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1

Conditional Logic: `if`, `else if`, and `else`

2m 26s
2

Switch Statements

4m 27s
3

Basic For Loop

6m 5s
4

While Loop: Basics

2m 26s
5

`do...while` Loop Explained

3m 12s
6

Nested Loops in JavaScript

5m 6s
7

`break` and `continue` in JavaScript Loops

5m 54s
4. Arrays, Objects and Iterables
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1

Basic Arrays in Javascript

2m 19s

Exploring Array Properties

2m 19s
3

Array Indexing, Access Elements

2m 32s
4

Array Iteration with JavaScript For Loops

2m 40s
5

Array Iteration: Using `for...of` in JavaScript

2m 5s
6

Basic Objects in JavaScript (Simple)

5m 8s
7

Basic This

1m 17s
5. Functions
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Basic functions

4m 40s
2

Return values from functions

3m 0s
3

Function Expressions

5m 22s
4

Arrow functions

2m 30s
5

"this" keyword in arrow functions

1m 17s
6. Promises, Async and Await
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7. The DOM
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