Product & software
TypeScript
A language and checking tool that adds static types to JavaScript, helping developers find incompatible operations before execution.
At a glance
- Foundation
- JavaScript
- Primary check
- Static type checking
Overview
TypeScript builds on JavaScript with a type system. It examines code before that code runs and reports operations that do not fit the declared or inferred types. This can reveal mistakes such as reading a property whose name does not exist on an object.
What the checker sees
The checker reasons about values and operations in a program. For example, it can detect a misspelled object property when the object's shape is known. Type information helps both the compiler and editor tooling explain mistakes.
Learning the relationship
JavaScript remains the foundation for understanding TypeScript behavior. The handbook introduces the two languages together and explains how the additional type layer relates to familiar JavaScript expressions, values, and program structure.
Sources and review
MOOR's explanatory text is supported by the following source links.
- TypeScript for the New Programmer — TypeScript
- TypeScript: supporting documentation — TypeScript