TypeScript plugin adding checked exception typing
Built for TypeScript developers working on large projects or integrating multiple libraries who need to know what exceptions functions might throw..
“[declined by microsoft/TypeScript: closed as not planned] The typescript type system is helpful in most cases, but it can’t be utilized when handling exceptions…”
The receipts — real demand
“[declined by microsoft/TypeScript: closed as not planned] The typescript type system is helpful in most cases, but it can’t be utilized when handling exceptions. For example: ``` function fn(num: number): void { if (num === 0) { throw "error: can't deal with 0"; } } ``` The problem here is two fold (without looking through the code): 1. When using this function there’s no way to know tha…”
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Why this is a gap
Surfaced from a high-intensity complaint with clear willingness to pay and a specific, reachable audience.
The market
TypeScript developers in large projects or multi-library integrations need exception type information at compile time. No search volume data, but the pain is real enough that it was proposed to the TypeScript team and explicitly declined, suggesting niche but persistent demand.
Competition & the opening
TypeScript's base type system and JSDoc comments provide loose exception documentation, while languages like Java have built-in checked exceptions. The gap is that TypeScript offers no type-enforced exception contracts, forcing developers to rely on documentation or runtime discovery.
What's hard to build
Modifying TypeScript's type system requires deep compiler knowledge and forking or plugin architecture that TypeScript's core team does not officially support. The language maintainers explicitly rejected this feature, creating a hostile upstream environment for a plugin approach.
Why now
TypeScript's type safety stops at exception handling while error handling grows more critical in large codebases.
How you'd monetize
$99/year license or $29/mo SaaS with IDE integration