What are the steps for examining a Type object using the TypeScript compiler API?

Note: This question is specifically regarding the TypeScript compiler API and not the TypeScript language itself!


I have a value that is of type ts.Type. My goal is to understand what kind of type it actually represents. Is it a number, a function, or perhaps an array?

After exploring, I discovered that by accessing type.flags, I can somewhat mimic the behavior of the static typeof operator. This helps me distinguish between primitive types like number, string, and boolean (excluding functions). Anything other than those primitives - such as arrays, functions, plain old JavaScript objects, etc. - will simply have the TypeFlags.Object flag.

My query now is: How can I delve deeper into these non-primitive types? What methods can I use to identify whether a type is an array, a function, an enum, a class instance, and so on?

Answer №1

For types with the Typeflags.Object attribute, there is an additional field known as type.objectFlags. This field allows for more specific differentiation of the type.

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