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JavaScript + Node.js — Beginner to Automation Engineer

JavaScript + Node.js —
From Beginner to Automation Engineer

28 days of hands-on JavaScript where you learn the language, understand the logic, and finish by writing real browser automation tests using Playwright — the skill employers pay for.

25+
Days of Training
14
Modules
100+
Topics Covered
100%
Interview-Ready

Who Is This Course For?

Built for complete beginners and manual testers who want to break into automation. You will learn JavaScript the way a professional uses it — with the Node.js runtime, a real code editor, and industry-standard tools. By the end you will have both the language skills and the test automation experience that employers look for.

Complete Beginners Manual Testers QA Job Seekers Career Changers Students

Your 28-Day Learning Path

Week 1 — Setup, data, calculations, and decisions
Week 2 — Loops, user input, and reusable functions
Week 3 — Object-oriented programming and JSON
Week 4 — Built-in tools, async code, and Playwright tests
01
Introduction & Setup
Days 1–2  |  Node.js, VS Code, and your first program
What You Will Learn
  • Install Node.js and VS Code; understand what each does
  • Run your first console.log() and see it in the terminal
  • Understand JavaScript as an interpreted language vs compiled languages
  • Know why Node.js lets you run JS outside a browser
  • Execute a .js file using node filename.js
  • Add single-line and multi-line comments to your code
  • Understand the JavaScript engine's read-execute cycle
  • Confirm your environment is fully ready before moving on
Why This Module

Every automation engineer writes JavaScript outside the browser — not inside it. Node.js is the engine behind Playwright, Jest, and almost every modern test framework. Getting comfortable with the terminal and console.log() now means you will never be blocked by "it won't run" problems later in the course.

02
Variables & Data Types
Days 3–4  |  var, let, const, primitives & objects
What You Will Learn
  • Declare variables with var, let, and const — and know when to use each
  • Work with primitive types: number, string, boolean, undefined, bigint, symbol, null
  • Create non-primitive types: objects {} and arrays []
  • Understand stack vs heap memory — where values live
  • Use template literals for clean, readable string formatting
  • Check a variable's type at runtime with typeof
  • Understand why null is a deliberate "nothing" and undefined is an accident
  • Avoid the most common beginner data-type bugs
Why This Module

Every test script stores something — a URL, a username, a list of test cases. Understanding the difference between a value that can change (let), one that is fixed (const), and one that leaks across blocks (var) saves you from mysterious bugs. This is also the number-one interview topic for JavaScript roles.

03
Operators
Days 4–5  |  Arithmetic, comparison, logical, and modern operators
What You Will Learn
  • Use arithmetic operators + − * / % ** for calculations
  • Shorthand assignment: += −= *= /= and increment/decrement ++ −−
  • Compare values with == (loose) vs === (strict) — and why strict matters
  • Combine conditions with &&, ||, and !
  • Write a one-line decision with the ternary operator ? :
  • Use ?? (nullish coalescing) as a default-value guard
  • Use ?. (optional chaining) to read nested values safely without crashing
  • Spread values ... to copy or merge arrays and objects in one go
Why This Module

Automation scripts are full of comparisons — "is this element visible?", "does the page title match?". Knowing the difference between == and === alone will save you from mysterious false-passes, and ?. is essential when reading data from APIs that might return incomplete responses.

04
Conditions
Days 6 & 12  |  if/else, switch, falsy values, and short-circuit logic
What You Will Learn
  • Write if / else if / else blocks to branch your program's path
  • Use a switch block to handle many fixed choices cleanly
  • Understand JavaScript's falsy values: 0, "", null, undefined, NaN, false
  • Use short-circuit evaluation — stop checking once the answer is clear
  • Know when to use strict equality === in conditions to avoid type coercion
  • Nest conditions correctly without creating hard-to-read pyramids
  • Predict what your program will do before running it
  • Avoid the single most common condition-writing mistake in JavaScript
Why This Module

Test assertions are just conditions — "if the button is not visible, fail the test". Understanding falsy values is critical because 0 and an empty string are falsy, which can make a passing assertion look like a failure if you use == instead of ===. Short-circuit logic also appears everywhere in Playwright's built-in helpers.

05
Loops
Days 7–10  |  for, while, for...of, forEach, nested loops
What You Will Learn
  • Repeat a block of code a fixed number of times with a for loop
  • Keep repeating until a condition becomes false with while
  • Guarantee at least one run with do...while
  • Walk through every item in an array with for...of
  • Loop through object keys with for...in
  • Use the forEach() array method for cleaner list iteration
  • Build nested loops to process grids and two-dimensional data
  • Choose the right loop type for arrays, objects, and sets
Why This Module

Automation without loops is just clicking one button. Real tests loop through hundreds of data rows, process all table cells, or retry a flaky step multiple times. Every data-driven test you ever write will be built on one of the loop patterns covered here — this is the module that turns you from a scripter into an automation thinker.

06
User Input & Loop Control
Days 11–12  |  prompt-sync, break, continue, return
What You Will Learn
  • Accept keyboard input at runtime using the prompt-sync package
  • Install a Node.js package with npm and import it correctly
  • Use break to exit a loop the moment you find what you need
  • Use continue to skip one iteration without stopping the loop
  • Use return to exit a function early and pass back a value
  • Build a simple interactive command-line menu
  • Understand the difference between pausing a step and ending the loop
  • Combine input and control flow to write logic-driven programs
Why This Module

Test runners are interactive programs — they read config, loop through test cases, and exit cleanly. Understanding break and continue also appears directly in automation helpers that retry or skip tests. return is how every Page Object method hands back data — getting comfortable with it now pays dividends from Module 9 onwards.

07
Functions Part 1
Days 13–14  |  Declaration, parameters, rest/spread, IIFE
What You Will Learn
  • Define a named, reusable block of code using function declaration
  • Pass values in as parameters and send results back with return
  • Provide default parameter values when no argument is supplied
  • Accept any number of arguments using rest parameters ...args
  • Store a function in a variable with a function expression
  • Write an IIFE (Immediately Invoked Function Expression) for one-off setup code
  • Understand scope — which code can see which variables
  • Write clean, reusable helpers that keep your scripts short and readable
Why This Module

Every Playwright action — page.click(), page.fill(), expect() — is a function call. Writing your own functions means you stop copying the same 10 lines into every test and instead write it once and call it everywhere. Functions are the single biggest step from "beginner" to "professional" code.

08
Functions Part 2
Days 14–16  |  Arrow functions, callbacks, higher-order functions, recursion
What You Will Learn
  • Write compact functions using arrow syntax () => {}
  • Pass a function as an argument into another function (callback pattern)
  • Build higher-order functions that accept or return other functions
  • Write a recursive function that calls itself to break a problem into steps
  • Visualise the call stack (LIFO) to understand the order of execution
  • Understand why arrow functions handle this differently from regular functions
  • See how callbacks power forEach, filter, map, and Playwright event handlers
  • Recognise these patterns instantly in any modern JavaScript codebase
Why This Module

Arrow functions and callbacks are the language of modern JavaScript. Every Playwright test body is a callback — test('name', async () => {...}). Every array method you will use in data-driven testing takes a callback. Understanding this module means you can read any open-source automation project and know exactly what is happening.

09
OOP — Classes & Objects
Days 17–19  |  class, constructor, this, static vs instance members
What You Will Learn
  • Define a class — a blueprint for creating objects
  • Create objects from a class using the new keyword
  • Use the constructor() to give each object its own starting values
  • Use this inside a class to refer to the current object
  • Write instance methods — actions that belong to one specific object
  • Write static methods — utilities that belong to the class itself, not any object
  • Model a real-world thing (e.g. a user account or a web page) as a class
  • Understand how the Page Object Model pattern is built on classes
Why This Module

The Page Object Model — the industry standard for organising automation tests — is just a class for each page. Each page has a constructor that takes the browser, and methods like login() or clickSubmit(). Once you understand classes properly you can read, write, and review Page Object code confidently in any team.

10
Encapsulation & Inheritance
Day 20  |  Private #fields, getters/setters, extends, super()
What You Will Learn
  • Declare private fields with #fieldName so only the class can access them
  • Provide controlled read/write access with get and set accessors
  • Create a child class that inherits all properties and methods of a parent with extends
  • Call the parent class's constructor using super()
  • Add unique features to a child class without touching the parent
  • Understand single, multilevel, and hierarchical inheritance patterns
  • Explain encapsulation in plain words in an interview
  • Apply inheritance to build a base test class all your test files extend
Why This Module

A professional test framework has a BaseTest class that handles browser setup and teardown — every individual test file simply extends BaseTest. That is inheritance in action. Encapsulation keeps the browser instance private so tests cannot accidentally reset it. This module turns classroom theory into the exact code structure used in production automation.

11
Polymorphism & OOP Pillars
Day 21  |  Method overriding, all four OOP pillars
What You Will Learn
  • Override a parent class method in a child class with a different implementation
  • Write code that works with any subtype without knowing exactly which one it is
  • Understand the four pillars: Encapsulation, Abstraction, Inheritance, Polymorphism
  • Give a clear, real-world example of each pillar in an interview setting
  • See how all four pillars work together in a professional test framework
  • Write a mini framework demo that uses all four concepts
  • Understand why test frameworks are built OOP-style and not just with functions
  • Feel completely confident in any object-oriented interview question
Why This Module

"Explain the four pillars of OOP" is asked in nearly every JavaScript automation interview. This module does not just list definitions — it shows each pillar in working code you wrote yourself over the previous two modules. That means you can explain them from personal experience, not from a memorised list, which is what interviewers actually want to hear.

12
Object Creation & JSON
Day 22  |  4 creation patterns, ?., ??, destructuring, spread
What You Will Learn
  • Create objects four ways: literal {}, constructor function, Object.create(), and class
  • Convert objects to JSON strings with JSON.stringify() and back with JSON.parse()
  • Read deeply nested values safely with optional chaining ?.
  • Set fallback values with nullish coalescing ??
  • Unpack object properties into named variables with destructuring const {a, b} = obj
  • Copy and merge objects cleanly with the spread operator ...obj
  • Understand how API responses are structured and how to read them safely
  • Use these techniques in data-driven test configurations
Why This Module

API testing with Playwright sends and receives JSON constantly. Destructuring lets you pull the fields you need from a response object in one line. Optional chaining prevents crashes when an API returns incomplete data. These patterns appear in every real-world JavaScript project — learning them here means you immediately look senior-level in a code review.

13
Built-in Methods — Strings, Arrays, Map & Set
Days 23–26  |  20+ string methods, array callbacks, Map, Set
String Methods (20+)
  • toUpperCase() / toLowerCase() — change letter case
  • trim() / trimStart() / trimEnd() — remove whitespace
  • slice() / substring() — extract part of a string
  • includes() / startsWith() / endsWith() — check for content
  • replace() / replaceAll() — swap text
  • split() — break a string into an array
  • indexOf() / lastIndexOf() — find position of text
  • repeat() / padStart() / padEnd() — formatting helpers
Array Methods (basic + callbacks)
  • push() / pop() / shift() / unshift() — add and remove items
  • filter() — keep only items that pass a test function
  • map() — transform every item into something new
  • reduce() — combine all items into one result
  • sort() — order items by a custom rule
  • find() / findIndex() — locate the first matching item
  • some() / every() — check if any or all items pass a test
  • flat() / flatMap() — flatten nested arrays
Map & Set
  • Use Map for key-value storage that remembers insertion order
  • Use Set for a list that automatically removes duplicates
  • Iterate Map and Set with for...of
  • Choose between Object, Array, Map, and Set for each use case
Why This Module

filter, map, and reduce are three of the most asked JavaScript interview questions. More practically, they replace dozens of manual loops in real automation code — filtering test data files, transforming API responses, and reducing result arrays to summary statistics. Mastering this module directly upgrades the quality and readability of every script you write.

14
Exception Handling & Async JavaScript
Days 27–28  |  try/catch, Promises, async/await, Playwright .spec.js
What You Will Learn
  • Wrap risky code in try/catch to prevent a crash from stopping the whole test run
  • Run a guaranteed clean-up block with finally
  • Identify error types: TypeError, ReferenceError, SyntaxError, RangeError
  • Create custom error classes to describe domain-specific failures
  • Start an async task and attach .then() / .catch() callbacks — the Promise pattern
  • Write async code that reads like synchronous steps using async/await
  • Run multiple async tasks in parallel with Promise.all()
  • Write a complete Playwright .spec.js test file that automates a real website
Interview Prep
var vs let vs const — what is the real difference?
var ignores block scope and is function-scoped, which causes bugs. let is block-scoped and mutable. const is block-scoped and cannot be reassigned. Always prefer const, use let only when the value must change, and avoid var.
== vs === — why does it matter?
== converts types before comparing, so "5" == 5 is true — a hidden surprise. === compares value AND type with no conversion, so "5" === 5 is false. Always use === in assertions.
Callbacks vs Promises vs async/await — when do you use each?
Callbacks are the oldest pattern and nest badly. Promises chain cleanly with .then(). async/await is Promises with synchronous-looking syntax — the standard in modern automation. Playwright uses async/await throughout.
What are the four pillars of OOP?
Encapsulation hides internal details. Inheritance shares behaviour between classes. Abstraction exposes only what is needed. Polymorphism allows one interface to work with multiple types. All four appear in every professional JS framework.
What is the difference between map() and filter()?
map() returns a new array of the same length where every item has been transformed. filter() returns a new array that may be shorter — it only keeps items where your function returns true.
What does this refer to inside a class method?
this refers to the specific object the method was called on — not the class itself. Each object gets its own copy of the data but shares the method code. Arrow functions inside a class inherit this from the outer scope instead of creating their own.