Why Our CTO Banned TypeScript After One Migration

At our company, TypeScript was the golden ticket. Strong types. Better tooling. Fewer bugs. We’d seen the hype. We’d read the case studies. “Just add types,” they said — so we did.

Six weeks later, our CTO banned it company-wide.

Here’s what happened.

The Dream: TypeScript Will Save JavaScript

We chose our messiest JavaScript codebase to migrate first. It was legendary. Undefined behaviors, mystery objects, runtime bugs that doubled as onboarding challenges. “TypeScript will ruin the fun,” some whispered.

They were right. The moment we added types, the chaos evaporated. We learned that half our function calls were guesses, most of our objects were lies, and null was basically the product manager.

The compiler was brutal, merciless — and correct. The codebase stabilized. Runtime errors plummeted. Confidence soared. Debugging became boring.

So why was TypeScript banned? Simple: it made us know what our code was doing.

The Problems Nobody Warned Us About

Developers Started Asking Questions

“Should this really be optional?”

“Wait, what is the type of this?”

“Why are we passing a string when the function expects an object with three nested keys and a discriminated union?”

Suddenly, devs were thinking before coding. Our velocity dropped — not from slowness, but from caution. Which, frankly, was worse.

Code Became Understandable

No more cargo cult copy-pasting from Stack Overflow. Types were self-documenting. Engineers actually read interfaces.

One junior engineer — new to the team — submitted a PR on their first day. It passed review with tests. HR flagged this as a possible anomaly.

Legacy Code Refused to Hide

As we typed more modules, the old sins surfaced. Code we hadn’t touched in years screamed under the new type system.

It was no longer possible to pretend the “utils” folder was fine. Worse, some files had to be deleted because we couldn’t figure out what they even did anymore.

The Tooling Was Too Honest

TypeScript’s language server was a snitch. VS Code auto-completions started revealing functions that shouldn’t exist. Linting tools no longer tolerated our spaghetti patterns.

TSConfig became the ultimate betrayal — we couldn’t hide behind any forever.

The Migration Solved Too Much

We expected less runtime bugs.

We didn’t expect to stop arguing about shape mismatches in standups.

PMs started using the word “predictable” when describing our estimates. QA stopped filing duplicate bug reports. Our lead engineer was spotted smiling during code review.

That’s when we knew we had a problem.

The Meeting That Killed TypeScript

In a company-wide retro, someone made the mistake of saying, “Honestly, this codebase kind of makes sense now.”

The CTO looked visibly shaken.

“If we keep this up,” he said slowly, “how will we differentiate between mid-levels and seniors?”

Then came the memo:

“Effective immediately: TypeScript is banned from production repositories. JavaScript will be our primary language of truth — flexible, expressive, and forgiving. Runtime errors are an opportunity for resilience. Let your intuition guide you, not the compiler.”

The justification? Here’s what the memo listed as “benefits of reverting to JavaScript”:

• Faster Prototyping: “Without strict types slowing us down, we can iterate like it’s 2013 again.”
• Creative Debugging Opportunities: “Null is a canvas. Type errors are puzzles for the curious.”
• Valuable Tribal Knowledge: “Understanding the codebase should require mentorship and senior guidance.”
• Job Security Through Ambiguity: “If everything is clear, how will we justify three-day bug hunts?”

Was TypeScript to Blame?

Absolutely. It gave us exactly what it promised: safety, clarity, and confidence.

But clarity is dangerous. It revealed bad patterns. Made poor decisions obvious. Gave juniors power seniors weren’t ready to share.

In a world built on duct tape and console.logs, TypeScript was simply too correct.

What We Use Now

We’re back to JavaScript. Loosely-typed, deeply-nested, and proudly dynamic. undefined is once again a feature. We’ve embraced any — spiritually, and technically.

Do we miss TypeScript? Only every time we ship to prod.

Do we regret the ban? Only when someone passes an array where a string was expected and prod goes down.

Final Thought

TypeScript doesn’t just improve your code — it exposes who’s been guessing.

And that’s why our CTO had to ban it after one dangerously transparent migration.