• Boolean Expressions

    • Operators

    Operators are symbols that perform actions on operands, which are values or variables. These allow you to edit data types.

    Mathematical Operators

    Mathematical operators allow you to perform arithmetic operations with data values.

    There are your conventional math operations

    Addition

    let sum = 1 + 2; // sum is 3

    Subtraction

    let difference = 2 - 1; // difference is 1

    Multiplication

    let product = 2 * 4; // product is 8

    Division

    let quotient = 6 / 3; // quotient is 2

    Then there are some others

    Modulus

    This operator gives you the remainder of the division between two operands.

    let remainder = 5 / 2; // remainder is 1

    Exponentation

    This operator raises the first operand to the power of the second.

    let power = 2 ** 4; // power is 16

    Increment

    This operator increases the value of the operand by 1.

    let value = 0;
value++; // value is now 1

    Decrement

    This operator decreases the value of the operand by 1.

    let value = 10;
value--; // value is now 9

    Here is an example of some of them in code.

    %% js

// additional ice for background
    const image_src_icesheet = path + "/images/gamify/icesheet.png";
    const image_data_icesheet = {
      name: 'icesheet',
      src: image_src_icesheet,
      pixels: {height: 70, width: 107},
      INIT_POSITION: { x: (width * 8 / 9), y: (height * 11 / 20) }, // multiplication
      SCALE_FACTOR: 5
    };

    String Operators

    String operators are able to manipulate different strings.

    Concatenation

    The concatentation operator (+) can combine strings.

    %%javascript

let string1 = "Hello";
let string2 = "everyone";
let combination = string1 + " " + string2; // empty quotes for a space
console.log(combination); // prints Hello everyone

    <IPython.core.display.Javascript object>

    Template Literals

    These use backticks (`) to be able to directly insert variables into a string by using ${variable name}.

    %%javascript

let variable = "user"
let greeting = `Hello ${variable}`;
console.log(greeting);

    <IPython.core.display.Javascript object>

    Boolean Expressions

    Boolean expressions are expressions that are either true or false. These can be essential in conditionals and loops.

    Here is an example of some below.

    %%javascript

loadLevel: function(targetLevelIndex = null) {
    console.log('Entering loadLevel method')
    // If targetLevelIndex is not empty/exists, then targetLevelIndex is set to currentLevelIndex
    const levelIndex = targetLevelIndex !== null ? targetLevelIndex : this.currentLevelIndex; // strict inequality
    
    // Greater than or equal to
    // If levelIndex is greater than or equal to the length of levelClasses, run stopTimer() and then return
    if (levelIndex >= this.levelClasses.length) {
        this.stopTimer();
        return;
    }
    GameEnv.continueLevel = true;
    GameEnv.gameObjects = [];
    this.currentPass = 0;
    
    const LevelClass = this.levelClasses[levelIndex];
    const levelInstance = new LevelClass(this.path);
    
    // console.log('Created levelInstance:', levelInstance);

    GameEnv.currentLevel = levelInstance;
    this.loadLevelObjects(levelInstance);

    this.transitionNPCS = [];
    this.transitionNPCS = levelInstance.transitionNPCS || [];
    console.log('Updated transitionNPCS in loadLevel:', this.transitionNPCS);

    // strict equality
    // If targetLevelIndex is empty then increment currentLevelIndex
    if (targetLevelIndex === null) {
        this.currentLevelIndex++;
    }
}

    Comparison Operators

    Equal to : ==