Narrow types in TimelineEvent so that it may be treated as a tagged union #4160
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joshuaobrien
commented
Nov 5, 2022
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| export interface CommentEvent { | ||
| id: number; | ||
| graphNodeId: string; |
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After narrowing the types, this line will throw an error without the addition of graphNodeId here:
I think TS was only incidentally happy before.
joshuaobrien
commented
Nov 5, 2022
| }, Object.create(null)); | ||
| } | ||
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| export class UnreachableCaseError extends Error { |
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A small helper for switch statements. It can be used to ensure that all variants of a tagged union are handled in a switch statement
joshuaobrien
changed the title
aeschli
approved these changes
Nov 7, 2022
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This PR narrows the types in
TimelineEventa bit by being explicit about the event types. This means that we can treatTimelineEventas a tagged union, which results in improved type safety and fewer lines of code.