The naming of TypeScript Union and Intersection types, with respects to type theory, used to be terribly confusing/contradictory: https://www.typescriptlang.or

The naming of TypeScript Union and Intersection types, with respects to type theory, used to be terribly confusing/contradictory: https://www.typescriptlang.org/docs/handbook/unions-and-intersections.html https://www.typescriptlang.org/docs/handbook/unions-and-inte... See last paragram under «Unions with common fields» Leading to terribly confusing TypeScript cheat sheets such as this (see the union and intersection venn-diagrams): https://carltheperson.com/images/magic-typescript/magic-typescript.png https://carltheperson.com/images/magic-typescript/magic-type... Compare with: https://en.wikipedia.org/wiki/Intersection_(set_theory) https://en.wikipedia.org/wiki/Intersection_(set_theory) Luckily TypeScript recently updated their docs, and the issue has been clarified in posts such as this: https://stackoverflow.com/questions/38855908/naming-of-typescripts-union-and-intersection-types/70513147#70513147 https://stackoverflow.com/questions/38855908/naming-of-types... Turns out, naming things is really hard, because what you implicitly refer to when you unionize or intersect turns out to be of vital importance.