Java Script Fundamentals - 2

1. console.log()

The console.log() method is used to print output to the browser’s console (or in the Node.js environment, to the terminal). It is useful for debugging purposes by displaying the value of variables, objects, or expressions.

Other variants in this are:

2. Template Literals

Template literals allow you to include expressions in a string and format it easily without the need for concatenation. They are enclosed by backticks (` ) and allow embedding variables using ${}

3. Comparison Operators

Comparison operators compare two values and return a Boolean (true or false).
For Numbers:

  • ==: Equal to (compares values, ignores type )

  • ===: Strict equal to (compares values and types)

  • !=: Not equal to (compares values, ignores type)

  • !==: Strict not equal to (compares values and types)

  • >: Greater than

  • >=: Greater than or equal to

  • <: Less than

  • <=: Less than or equal to

For Non-Numbers:

JavaScript uses a lexicographical (alphabetical) comparison for strings:

For objects, it compares references:

4. Conditional Statement

Conditional statements are used to perform different actions based on different conditions.

  1. if Statement

    The if statement executes a block of code if a specified condition is true.

  1. else if Statement

    The else if statement adds another condition to an if statement. If the first condition is false, it checks the next one.

  1. Nested if-else

    You can nest if statements inside other if or else blocks.

  1. Switch Statement

    The switch statement is used to execute one block of code among many options

5. Logical Operator

Logical operators are used to combine conditions in if statements.

  • && (AND): Returns true if both conditions are true

  • || (OR): Returns true if at least one condition is true

  • ! (NOT): Inverts the value of a boolean

6. Truthy And Falsy

In JavaScript, some values are inherently truthy or falsy in conditional statements.

  • Falsy values: false, 0, "" (empty string), null, undefined, NaN

  • Truthy values: All other values, including non-empty strings, objects, arrays, and true

7. Alerts And Prompts

  • alert(): Displays a message to the user in a dialog box

  • prompt(): Displays a dialog box with a text input field. The user’s input is returned