If you have ever worked on a web development project, you have probably already encountered JavaScript. Indeed, it has long been the most popular scripting language.
TypeScript, on the other hand, is a programming language better suited to large applications: open-source, it was developed by Microsoft in 2012, mainly because JavaScript code was becoming too complex to manage for large-scale applications.
TypeScript is a superset of JavaScript: in general, any code written in JavaScript is also valid in TypeScript.
In short, JavaScript + more features = TypeScript.
Thus, if you save your JavaScript file (.js) with a TypeScript extension (.ts), it will still work perfectly. However, be careful about jumping to conclusions: this does not mean that TypeScript and JavaScript are identical.
Before outlining the differences between the two, let’s understand what each language looks like!
JavaScript
Often abbreviated as JS, JavaScript is a software design language that follows the ECMAScript specification. JavaScript is compiled immediately before execution.
It features dynamic typing, brace-based syntax, first-class functions, and prototype-based object orientation. Along with CSS and HTML, JavaScript is one of the fundamental technologies of the Web.
JavaScript allows you to create interactive web pages, which are an essential aspect of modern websites. Since the vast majority of websites use it for client-side page behavior, it makes sense that all web browsers include a dedicated JavaScript engine for this purpose. Note that while JavaScript engines used to exist only in web browsers, they are now embedded in some servers (typically via Node.js). There are many derivatives of JavaScript such as TypeScript, CoffeeScript, Dart and Kotlin.
These are also embedded in multiple applications built with frameworks such as Cordova and Electron.
As a programming language As a multi-paradigm language, JavaScript supports imperative, event-driven, and functional styles and provides an application programming interface (API) that lets it handle dates, text, standard data structures, the Document Object Model (DOM), and regular expressions.
Advantages of JavaScript
JavaScript can be considered the perfect solution for small web projects and small teams. It is common to use JavaScript without build tools, and if you rely on frameworks, some of them do not support TypeScript.
Additionally, by using libraries and existing JavaScript frameworks, you can develop web applications faster while streamlining your software development process.
TypeScript needs you to install the JS libraries you want to use: an additional type definition translates into an additional epm package… It is therefore preferable to use a popular JavaScript library for your development, as it will be properly maintained in the future.
TypeScript
TypeScript is an object-oriented, open-source programming language. Created and maintained by Microsoft, TypeScript is actually a syntactic superset of JavaScript, adding optional static typing along the way.
TypeScript is intended for building large applications and transpiles to JavaScript.
Common JavaScript programs are also valid TypeScript programs, and the language can be used to create JavaScript applications for server-side execution as well as client-side.
There are many alternatives for transpiling TypeScript to JavaScript; you can use the default TypeScript checker or the Babel compiler.
TypeScript supports files that can include the type data of current JavaScript libraries, just like header files C++ can define the construction of current object files, allowing other programs to exercise the values defined in the files as if they were statically typed TypeScript entities.
There are third-party header files for prevalent libraries like D3.js, jQuery, and MongoDB. TypeScript headers for core Node.js modules are also available, enabling the development of Node.js programs in TypeScript.
The TypeScript compiler is written in TypeScript and compiled to JavaScript. It is released under the Apache 2.0 license.
Advantages of TypeScript
TypeScript is ideal for large-scale projects or when your team has many developers working on a big project — in such cases TypeScript is a better option than JavaScript. TypeScript's access modifiers and interfaces can also help clarify APIs.
If your project uses React and your team is not familiar with its API, TypeScript provides type definitions. You can also use IntelliSense, which helps you navigate and verify new interfaces.
Writing plain JavaScript code isn't always easy, especially if you prefer compile-time error checking: with TypeScript, it's possible to perform runtime type assertions as well as compile-time validation.
What are the differences between TypeScript and JavaScript?
Ecosystem
The TypeScript ecosystem is intuitive and powerful, allowing you to statically type various idiomatic JavaScript patterns such as intersections, union types, and discriminated unions.
JavaScript, on the other hand, lets you explore and code without a build step.
Data binding
TypeScript uses concepts such as interfaces and types to define the data being used.
No such notion exists in JavaScript...
Learning curve
TypeScript has a fairly steep learning curve and requires advanced scripting knowledge.
JavaScript, by contrast, is easy to learn and is a flexible language for writing scripts.
npm packages
With TypeScript, countless npm packages include static type definitions (or have external ones that are easier to install).
JavaScript has the ability to discover and author code, still without any build step.
Annotation and typing
To get the most out of these features, TypeScript developers must constantly annotate code, whereas no annotations are required for JavaScript.
Compiler
TypeScript code must be compiled, whereas there is obviously no requirement to compile JavaScript code.
Client-side / server-side
Although it can be used server-side, TypeScript is mostly used client-side.
JavaScript is used both on the server side and on the client side.
Community
TypeScript has a smaller developer community than JavaScript, the latter being far more popular among software developers.
Conclusion
Observing the differences between TypeScript and JavaScript, we can say that both technologies, while similar, have their advantages and disadvantages.
Indeed, JavaScript may not be the most comprehensive programming language, but it is used with HTML to improve the quality of web pages. In addition, there are thousands of experienced developers who code in JavaScript and is supported by all browsers.
TypeScript, on the other hand, is a preferred option for developers who want to produce clean, tidy, compact, and readable code. Not to mention the various advantages TypeScript offers in terms of live error checking and static typing. The major drawback of TypeScript is that it is not yet native in all web browsers, unlike JavaScript.
The conclusion will therefore recap what we learned at the start of the article: JavaScript is best suited when you have a small team working on small web projects. Conversely, if you have a more experienced team with solid knowledge and you want them to handle a more complex project, then TypeScript is the wiser choice.
Even presented as a "Super JavaScript", TypeScript is not intended to replace or make JavaScript obsolete: JavaScript endures and remains the most popular client-side scripting language. Moreover, for the smallest projects, using TypeScript can be an overhead, because transpiling code to JavaScript takes time, which is an extra step for rendering. Since JavaScript is executed directly in the browser, it's easier to refresh or debug code for small scripts, whereas with TypeScript the developer will need a IDE and an appropriate configuration to run their code.
Whatever your preference, you will be able find developers on Codeur.com to strengthen your team. Describe your TypeScript or JavaScript project for free on the platform to receive quotes from our freelance experts.
