Types in Depth

Types in Depth

In this lesson — part of Data Deep Dive — you'll learn types in depth in JavaScript and why it matters in real work.

Why it matters

Types tell you what operations make sense and catch whole classes of bugs early.

Key ideas

• Common types: text, numbers, booleans
• Type conversion and coercion
• When to be explicit about types
• Type errors and how to read them

In practice

Here's how it looks in idiomatic JavaScript:

const n = 42;              // number
const s = "42";            // string
const flag = true;         // boolean
const asNum = Number(s);    // string -> number
console.log(typeof n, typeof s, asNum + 1); // number string 43

JavaScript note: JavaScript has one number type (IEEE-754 double) for both integers and floats, plus typeof to inspect a value's primitive type at runtime.

Try it yourself

Exercise: In JavaScript, convert a number to text and back, and print both.

Recap

You now understand types in depth and can apply it in JavaScript. Mark this lesson complete and continue to the next one.