TypeScript Is Just JavaScript with Extra Steps: Change My Mind

TypeScript continues to grow in popularity, with the 2024 Stack Overflow Developer Survey showing it as the 4th most loved language. Its advocates praise its type safety, improved developer experience, and enhanced tooling. But a persistent counter-argument remains: TypeScript is just JavaScript with extra steps.

Let's examine this claim objectively and see if it holds water.

What TypeScript Actually Is

At its core, TypeScript is a superset of JavaScript that adds optional static typing. It compiles down to plain JavaScript, which means browsers and Node.js run the JavaScript output, not the TypeScript itself.

This fundamental architecture leads to some interesting consequences:

// This TypeScript code
function add(a: number, b: number): number {
  return a + b;
}

// Becomes this JavaScript
function add(a, b) {
  return a + b;
}

The types are completely erased during compilation. They exist solely during development.

The "Extra Steps" Argument

Critics of TypeScript point to several "extra steps" that complicate the development process:

1. Compilation step: TypeScript requires a build process, adding complexity to the development workflow
2. Type definitions: For third-party libraries without built-in types, you need to install separate @types/* packages
3. Configuration overhead: Managing tsconfig.json with its 100+ options
4. Learning curve: Understanding advanced type concepts like generics, conditional types, and utility types
5. Type maintenance: Keeping types updated as code evolves

These extra steps require time and cognitive effort that could otherwise be spent writing actual business logic.

The Runtime Reality

Perhaps the strongest argument supporting the "just JavaScript with extra steps" claim is that TypeScript provides zero runtime benefits. All the type checking happens during development and compilation, not when your code is actually running.

// This code will compile but fail at runtime
const apiResponse: User = await fetchData();
const username = apiResponse.name.toUpperCase();

If apiResponse doesn't match the User type at runtime (for example, if the API changes), the TypeScript compiler won't save you. The error will still happen in production.

The Type Illusion

TypeScript creates what some call a "type illusion" – the feeling of complete safety when in reality there are numerous escape hatches:

// All of these break the type system
const danger1 = JSON.parse(someString) as SafeType;
const danger2 = someValue as any as SafeType;
const danger3: SafeType = Object.assign({}, someObject);

Each of these constructs allows developers to tell the compiler "trust me" while potentially introducing type inconsistencies that will only be discovered at runtime.

The Maintenance Burden

TypeScript codebases typically contain significantly more lines of code than equivalent JavaScript implementations. This is due to:

• Type definitions
• Interface and type declarations
• Generic type parameters
• Type assertions and guards

This additional code must be maintained, understood, and debugged alongside the actual functionality.

The Developer Experience Trade-off

TypeScript offers undeniable developer experience benefits:

• Better autocompletion
• Inline documentation
• Early error detection
• Safer refactoring

But these benefits come at a cost of complexity, verbosity, and development overhead. Is the trade-off worth it?

// JavaScript version - 1 line
const getUser = (id) => fetchUser(id);

// TypeScript version - 7 lines
interface User {
  id: string;
  name: string;
  email: string;
}

const getUser = async (id: string): Promise<User | null> => fetchUser(id);

The "Types Are Documentation" Myth

Proponents often claim that TypeScript serves as self-documenting code. While types do provide some information about expected data structures, they often fail to capture:

• Business rules and invariants
• Performance characteristics
• Side effects
• Error conditions
• Usage patterns

Proper documentation and tests remain necessary regardless of TypeScript usage.

When "Extra Steps" Add Real Value

Despite the criticisms, TypeScript's extra steps do add significant value in specific contexts:

1. Large codebases: Type information becomes increasingly valuable as project size grows
2. Team environments: Types create contracts between different parts of an application
3. Complex domain models: Modeling complex business rules with types can prevent logical errors
4. Public APIs: Types provide clear interfaces for consumers

Alternative Approaches

For those unconvinced by TypeScript, some alternatives offer partial benefits with fewer "extra steps":

• JSDoc annotations: Add type information as comments, leveraging VS Code's JavaScript type inference
• PropTypes: Runtime type checking for React components
• Runtime validation libraries: Zod, Joi, or Yup for validating data at runtime
• Test-driven development: Comprehensive tests can catch many issues TypeScript addresses

The Case for Plain JavaScript

Modern JavaScript has evolved significantly:

• ES modules provide better code organization
• Classes offer structured OOP
• Async/await simplifies asynchronous code
• Optional chaining (?.) and nullish coalescing (??) handle common null cases

With these improvements and good testing practices, many projects can thrive without TypeScript's extra complexity.

The Pragmatic Middle Ground

Perhaps the most reasonable position is neither wholesale adoption nor rejection of TypeScript, but a pragmatic approach:

• Use TypeScript for core libraries, APIs, and complex business logic
• Consider plain JavaScript for prototypes, simple scripts, and learning projects
• Apply TypeScript gradually in existing projects, focusing on high-value areas
• Use "strict: false" and fewer type annotations when starting out

Conclusion

The claim "TypeScript is just JavaScript with extra steps" is technically accurate but reductive. The real question isn't whether TypeScript adds steps—it certainly does—but whether those steps provide enough value to justify their cost in your specific context.

TypeScript doesn't make impossible things possible; it makes difficult things easier at the expense of making simple things slightly more complex.

What's your experience? Do you find TypeScript's extra steps worthwhile, or do you prefer the simplicity of plain JavaScript? Share your thoughts in the comments.