storybookjs/storybook

[Bug]: Autodocs "union" type

Open

#25305 opened on Dec 22, 2023

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 (9 comments) (1 reaction) (0 assignees)TypeScript (89,909 stars) (10,058 forks)batch import
argtypesbughelp wantedreacttypescript

Description

Describe the bug

I have defined some props on the component with union. For example:

export interface MyComponentProps { title: string; subtitle?: string | undefined; }

I wrote a story for my component, added "autodocs" to tags and Storybook generated controls but for prop subtitle I got type union. I expected to see string | undefined.

To Reproduce

Add prop type for example string | undefined.

System

storybook: 7.6.5 @storybook/vue3: 7.6.5 @storybook/vue3-vite: 7.6.5

Additional context

No response

Contributor guide

Tech stack
vuetypescript
Domain
documentation
Issue type
bug
DifficultyEstimated implementation difficulty for a new contributor, from 1 for very small changes to 5 for expert-level work.
3
Estimated timeA rough time range for an experienced contributor to investigate, implement, test, and prepare a pull request.
half day
Activity statusHow available the issue appears right now: fresh, active, stale, blocked, or waiting on maintainer input.
active
ClarityHow clearly the issue explains the expected change, acceptance criteria, and next step.
clear
Prerequisites
Basic knowledge of TypeScript typesFamiliarity with Storybook autodocsVue component basics
Newbie friendlinessA 1-100 score estimating how approachable this issue is for first-time contributors.
65
Research direction
Investigate how the Storybook autodocs system renders union types like 'string | undefined'. The issue suggests that it currently outputs 'union' instead of the actual type. Look at the type renderer in the autodocs addon (likely components related to PropRow or ArgTable) to see how it resolves union types. Check if there's a missing case in the type mapping. See comments for any additional clues.