TypeScript
TypeScript adds a static type system to JavaScript. It assists development but does not replace checks on actual incoming data.
Find type errors before execution
TypeScript extends JavaScript with a static type system. During development, it can flag incompatible values and missing properties. The errors it detects also depend on settings and the types used.
In a fictional ordering module, quantity: number expects a number. If the checked program code assigns the text "two" instead, type checking can report the conflict. This helps when working on connected functions.
The type annotation does not, however, check arbitrary data arriving later through an API. The application needs actual input validation at runtime. A number may also violate a quantity rule. TypeScript is therefore a development aid for JavaScript code; it proves neither business correctness nor an error-free overall flow.
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Related terms
- JavaScriptJavaScript is a programming language for application logic, in browsers and elsewhere. Its role differs from HTML and CSS.
- BackendThe backend handles an application’s server-side rules and data. It is more than a database or an administration screen.
- Legacy systemAn existing system still in use, with technical and business dependencies accumulated over time.
- Multi-tenancyMulti-tenancy supports separate customer or group scopes in one solution. A tenant is not automatically one person or one database.
- Browser cacheThe browser cache stores suitable HTTP responses for later use. Reuse and revalidation follow the applicable rules.
- Cache invalidationCache invalidation ends reuse of a stored copy under defined rules. The source record remains a separate concern.
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