Functions, Parameters & Return Values

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Structure logic into reusable functions, pass arguments, return calculated values, and prevent code duplication.

The Building Blocks of Modularity

A function is a self-contained block of code designed to perform a specific task. Functions take input arguments, execute algorithmic logic, and return an output.

Pure Reusable Function

Try It Yourself »

function calculateTax(subtotal, taxRate = 0.08) {
  if (subtotal < 0) throw new Error("Subtotal cannot be negative");
  return Number((subtotal * (1 + taxRate)).toFixed(2));
}

console.log("Total Order:", calculateTax(150.00)); // 162.00

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Test Yourself With Exercise

+15 XP

What keyword passes the final computed result from inside a function back to the calling code?

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