While JavaScript is frequently the language of choice for all sizes of frontend and backend applications, it's not the only option. Nor is it necessarily the most efficient or cost-effective. Increasingly, TypeScript is becoming the go-to language for app development ─ particularly for larger apps. The time- and cost-saving benefits are significant enough that some organizations are even taking projects initially started in JavaScript and migrating them to TypeScript.

What is TypeScript?

While the number of programs written in JavaScript has grown exponentially, the programming language's ability to express the relationships between different units of code and mitigate coding errors early on hasn't kept pace. Along with JavaScript's inconsistent semantics, this makes JavaScript-driven app development difficult to manage at scale.

Released in 2012, TypeScript was created to address JavaScript's deficiencies in developing large-scale apps. It's an open source, strongly typed programming language that builds on JavaScript by adding optional static typing. Types enable structuring and validating code before it's executed, which is beneficial in developing large apps. They also provide additional information about code, which serves as better documentation for other developers and facilitates collaboration.

TypeScript is a superset of JavaScript, which means any JS code is also valid TS code ─ provided the TS configuration is set to be compatible with it. It outputs code in pure JavaScript and allows developers to liberally use JS libraries, tools, and frameworks. It runs on Node.js or any browser that supports ECMAScript 3 or higher. It also supports object-oriented programming features.

JavaScript Drawbacks

JavaScript is one of the world's most popular programming languages and works extremely well for small projects. However, its disadvantages ─ many of which affect projects costs and code delivery time ─ make a strong case for considering alternatives such as TypeScript, particularly for larger projects.

Much of it has to do with the lack of types and compile-time error checks, making JavaScript less than desirable for server-side code in enterprises and large codebases. The following are just a few of its disadvantages:

• JavaScript employs dynamic typing, which means scripts can compile even if they contain errors that can prevent them from properly running.
• Because JavaScript is dynamically typed, it allows one variable to have multiple properties assigned to it. It doesn't instantly let developers know what a variable can contain. That makes it easy to assign the wrong properties.
• Since JavaScript is an interpreted language, errors can only be found during run-time. Code needs to run first to be tested and validated, so it can take considerable time to find bugs and errors in the code.
• To eliminate inaccuracies, it's necessary to manually verify types and the syntactic correctness of the code. This lengthens development time and extends the delivery cycle to production, increasing development costs.
• JavaScript code is executed on the client-side, so it's viewable to the user. As a result, bugs and oversights have the potential to be exploited for malicious purposes.
• Lengthy onboarding of new developers can result because developers must figure out the properties of the structures they're working with, as well as the data types. While JSDoc can be used for documenting code and annotating types, there's still the need to synchronize the actual code and documentation. The lack of synchronization, in turn, can mislead developers and complicate the introduction of new, business-requested features.
• JavaScript is prototype-based, not class-based. It's not considered a pure object-oriented programming language, although it can follow some object-oriented programming principles.

The TypeScript Advantage

TypeScript is a superset of JavaScript. If a developer knows JavaScript, there's not much of a learning curve to take advantage of the features TypeScript offers that make up for many JavaScript's deficiencies ─ and offer additional benefits.

For example, with JavaScript, variables can start as one property, and then change into an object or a string. These inconsistencies can generate problems that are difficult to resolve in large apps. TypeScript, on the other hand, analyzes the code and tries to determine proper variable types prior to runtime. Once a variable type is assigned, it stays unchanged. TypeScript's compiler also helps shorten the QA and testing process in later stages of development.

TypeScript also helps developers quickly figure out the purpose of a variable within the code. It can also suggest available properties in functions, classes, or components. Being able to quickly lookup a variable is important because it reduces the likelihood of calling the wrong function or accidentally skipping a variable declaration. Any reduction in bugs and errors reduces the time required for fixing those issues and in overall development time. That gives developers more time to work on app logic and fix errors that can be detrimental to in-app performance and usability. According to a postmortem analysis by Airbnb, 38% of bugs were preventable with TypeScript after the company adopted it throughout the organization.

As a static language, TypeScript performs type checks upon compilation, flagging type errors and helping developers spot mistakes early on in development. Reducing errors when working with large codebases can save hours of development time.

Clear and readable code is easy to maintain, even for newly onboarded developers. Because TypeScript calls for assigning types, the code instantly becomes easier to work with and understand. In essence, TypeScript code is self-documenting, allowing distributed teams to work much more efficiently. They don't have to spend inordinate amounts of time familiarizing themselves with a project.

TypeScript's integration with editors also makes it much easier to validate the code thanks to context-aware suggestions. TypeScript can determine what methods and properties can be assigned to specific objects, and these suggestions tend to increase developer productivity.

TypeScript is widely used to automate the deployment of infrastructure and CICD pipelines for backend and web applications. Moreover, the client part (for example, when using Angular) and the backend can be written in the same language - TypeScript. This flexibility allows an engineer who knows one programming language to cover all parts of the system.

Because TypeScript essentially transpiles to JavaScript, migrating existing code to TypeScript is easy and fast. It can typically be accomplished simply by running the compiler and adding typing where it's not recognized by the language. There's no need to make changes to the code.

The benefits of TypeScript have been noticed by developers. TypeScript was used by 78% of the 2020 State of JS respondents, with 93% saying they would use it again. Typescript continues to grow in popularity. It was voted the second most loved programming language in the Stack Overflow 2020 Developer survey.

TypeScript & AWS: Better Together

There's another compelling reason to consider TypeScript for large-scale app development projects. It's fully supported by AWS, the leading cloud platform for modern app design and development as noted in Gartner's Magic Quadrant for Cloud Infrastructure and Platform Services.

The following services and tools have seamless integration out-of-the-box with TypeScript, enabling you to use this language for a vast number of tasks:

• AWS CDK provides Infrastructure as code (IaC) to deploy the entire infrastructure in one click in an automatic mode. You can also automate the creation of CI/CD pipelines for the future launch of specific jobs on demand.
• AWS Lambda allows you to run computation tasks in serverless mode using automatic scaling and an efficient pricing scheme.
• Amazon EC2, ECS, and EKS can cover any of your tasks and provide a wide range of solutions for running apps written in TypeScript - from bare metal servers to complex clusters of hundreds of Docker containers.

Optimize Your Application Development Projects

All decisions made during an application development project can impact overall costs and time to market. That includes going with the right programming language and using the most appropriate cloud platform and resources.

When approaching an app dev project, a one-size-fits-all approach rarely works. Take the time to define your needs and priorities and select the best resources to deliver the best results.

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ABOUT THE AUTHOR

Vyacheslav Gorlov is the Head of Data Science at ClearScale.