In TypeScript, function parameters are checked bivariantly by default for method declarations. What does this mean?

Question

TypeScript Professional — Hard

In TypeScript, function parameters are checked bivariantly by default for method declarations. What does this mean?

Accepted Answer

In TypeScript, bivariant checking means that function parameters are checked for both covariance and contravariance. This allows parameters to be supertypes or subtypes, ensuring flexibility in method declarations.