[Bug]: CSF Parsing error: Expected 'ObjectExpression' but found 'undefined' instead in 'Identifier'.

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89,909 stars (89,909 stars)

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Avg merge 9d 3h (Avg merge 9d 3h)173 merged PRs in 30d (173 merged PRs in 30d)

Description

System:
    OS: Linux 5.15 Ubuntu 24.04.2 LTS 24.04.2 LTS (Noble Numbat)
    CPU: (20) x64 13th Gen Intel(R) Core(TM) i7-13800H
    Shell: 5.9 - /home/linuxbrew/.linuxbrew/bin/zsh
  Binaries:
    Node: 22.14.0 - /home/linuxbrew/.linuxbrew/opt/node@22/bin/node
    Yarn: 1.22.22 - /home/linuxbrew/.linuxbrew/bin/yarn
    npm: 10.9.2 - /home/linuxbrew/.linuxbrew/opt/node@22/bin/npm
    pnpm: 10.8.0 - /home/linuxbrew/.linuxbrew/bin/pnpm
  npmPackages:
    @storybook/addon-a11y: ^8.6.11 => 8.6.11
    @storybook/addon-coverage: ^1.0.5 => 1.0.5
    @storybook/addon-essentials: ^8.6.11 => 8.6.11
    @storybook/addon-interactions: ^8.6.11 => 8.6.11
    @storybook/addon-links: ^8.6.11 => 8.6.11
    @storybook/blocks: ^8.6.11 => 8.6.11
    storybook: ^8.6.11 => 8.6.11
    storybook-addon-rslib: ^1.0.1 => 1.0.1
    storybook-react-rsbuild: ^1.0.1 => 1.0.1

Contributor guide

Research direction

The bug is in CSF parsing, likely in the storybook core. Start by reproducing the issue using the provided repo. Search the codebase for the error string 'Expected ObjectExpression but found undefined instead' to locate the relevant parser. Check the packages that handle CSF (e.g., @storybook/core server, @storybook/csf tools). Look at recent commits that might have introduced a regression. The reproduction uses storybook react rsbuild, so also examine the integration with rsbuild.

Tech stack

typescriptjavascriptreactnodejs

Domain

frontendtoolingdeveloper experience

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.

1-3 hours

Activity statusHow available the issue appears right now: fresh, active, stale, blocked, or waiting on maintainer input.

Fresh

ClarityHow clearly the issue explains the expected change, acceptance criteria, and next step.

Clear

Prerequisites

JavaScriptStorybook basics

Newbie friendlinessA 1-100 score estimating how approachable this issue is for first-time contributors.

60