intermediate

Advanced Language Features in JavaScript

Software Engineering

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Go beyond ES5 basics into the modern JavaScript that powers real-world codebases: ES2015+ syntax, functional patterns, class-based OOP, Symbols and iteration protocols, async/await, and Proxy-based meta-programming.

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Upgrade from ES5-era JavaScript to modern (ES2015+) syntax. This course covers the everyday building blocks that make modern code concise and expressive: block-scoped variables, arrow functions, destructuring, spread/rest, optional chaining, nullish coalescing, and template literals (including tagged templates). By the end, you'll read and write idiomatic modern JavaScript fluently.

Course 2

Functional Programming Patterns in JavaScript

5 lessons

20 practices

Adopt the functional mindset that powers modern JavaScript codebases. This course teaches closures, higher-order functions, immutable updates, currying, function composition, memoization, and modern collections (`Map`/`Set`). You'll learn to build small, composable utilities that combine into clean data pipelines.

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Course 3

Modern Object-Oriented JavaScript

5 lessons

20 practices

Model domain entities with confidence using modern class features. This course explores the prototype model beneath classes, then layers on private fields, static members, getters/setters, inheritance with `super`, custom error subclasses, `instanceof`, and `WeakMap`-based privacy as an alternative. You'll learn when to choose each tool and how to keep class designs robust.

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Course 4

Symbols, Iteration, and Asynchronous JavaScript

5 lessons

20 practices

Master the protocols and async machinery powering modern JavaScript: Symbols, iterators, generators, lazy pipelines, Promises, `async`/`await`, and async iteration with `for await…of`. Write code that integrates naturally with language features.

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Course 5

Meta-Programming and Advanced Integration Patterns

4 lessons

17 practices

Reach the most powerful corners of the language. This course covers `Proxy` and `Reflect`, reactive systems, tagged-template DSLs, and combines OOP, functional pipelines, and async iteration into a cohesive capstone program.

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From our community

Hear what our customers have to say about CodeSignal Learn

I'm impressed by the quality and can't stop recommending it. It's also a lot of fun!

Francisco Aguilar Meléndez

Data Scientist

+11

I love that it's personalized. When I'm stuck, I don't have to hope my Google searches come out successful. The AI mentor Cosmo knows exactly what I need.

Faith Yim

Software Engineer

+14

It's an amazing product and exceeded my expectations, helping me prepare for my job interviews. Hands-on learning requires you to actually know what you are doing.

Alex Bush

Full Stack Engineer

I'm really impressed by the AI tutor Cosmo's feedback about my code. It's honestly kind of insane to me that it's so targeted and specific.

Abbey Helterbran

Tech consultant

I tried Leetcode but it was too disorganized. CodeSignal covers all the topics I'm interested in and is way more structured.

Jonathan Miller

Senior Machine Learning Engineer

+12

I'm impressed by the quality and can't stop recommending it. It's also a lot of fun!

Francisco Aguilar Meléndez

Data Scientist

+11

Advanced Language Features in JavaScript

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Join the 1M+ learners on CodeSignal

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