Glossary

T

Type loosing

Type loosing: The process of increase possibility of types or broadening types when converting from one type to another.

For example, when you convert from 'UP' to 'UP' | 'DOWN', you are broadening the type. That's means you are loosing type information. because the possibility of types is increased, not only 'UP' but also 'DOWN'.

Type tightening

Type tightening: The process of decrease possibility of types or narrowing types when converting from one type to another.

For example, when you convert from 'UP' | 'DOWN' to 'UP', you are narrowing the type. That's means you are tightening type information. because the possibility of types is decreased, not only 'UP' | 'DOWN' but also 'UP'.