You pretty much act as you do with regular type systems, rarely creating types that are compatible by accident. There is one place however where you use structural typing constantly.

TypeScript is a superset of JavaScript and using "options" objects as method parameters is a common pattern. These options objects are synonymous with anonymous classes and don't have a name, only a shape. Structural typing is one of the strategies TypeScript uses to maintain compatibility with patterns in JavaScript that use these nameless objects.

There are no namespaces. Methods are compatible if they take the same or a subset of the parameters. Objects need to have matching property names and values.