WDD 131: Dynamic Web Fundamentals

JavaScript: Fundamental Programming Constructs

Overview

Through the prerequisite programming courses, you have built a foundational understanding of common, programming constructs, including operators, expressions, decision structures, loops, and functions. This activity focuses on a few of the common control structures in programming.

Prepare

Below are some of the most common controls structures, or building blocks, in JavaScript:

• Conditional Statements:
  • if statement: Executes a block of code if a specified condition is true.

    if (condition) {
      // Code to execute if the condition is true
    }

    The condition is evaluated to a boolean value, i.e., true or false. Writing condition statements is a critical skill in programming. The use of operators and expressions is a key concept in writing condition statements that solve programming problems.
  • else statement: Provides an alternative block of code to execute if the condition in the if statement is false.

    if (condition) {
      // Code to execute if the condition is true
    } else {
      // Code to execute if the condition is false
    }

  • else if statement: This structure allows for the checking of multiple conditions in sequence.

    if (condition1) {
      // Code to execute if condition1 is true
    } else if (condition2) {
      // Code to execute if condition2 is true
    } else {
      // Code to execute if none of the conditions are true
    }

• Switch Statements: Provides a way to execute selective blocks of code based on the value of an expression.

  switch (expression) {
    case value1:
      // Code to execute if expression is equal to value1
      break;
    case value2:
      // Code to execute if expression is equal to value2
      break;
    // ... more cases ...
    default:
      // Code to execute if none of the cases match
  }

• Looping Statements:
  • for Loop: Repeats a block of coe a specified number of times.

    for (let i = 0; i < 19; i++) {
      // Code to execute in each iteration
    }

  • while Loop: Repeats a block of code as long as a specified condition is true.

    while (condition) {
      // Code to execute while the condition is true
    }

  • forEach Loop: This loop structure is for arrays. It iterates over each element of the array.

    array.forEach(function(element) {
      // Code to execute for each element
    });

Activity Instructions

1. Ponder: Repitition Structures