fix(next): improve getStaticPaths error message for non-string params#89418
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bukamasedo wants to merge 2 commits intovercel:canaryfrom
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fix(next): improve getStaticPaths error message for non-string params#89418bukamasedo wants to merge 2 commits intovercel:canaryfrom
bukamasedo wants to merge 2 commits intovercel:canaryfrom
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When developers accidentally pass non-string values to path parameters, the error message is now clear instead of cryptic TypeError. fixes vercel#41281
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timneutkens
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Feb 3, 2026
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| const invalidElement = paramValue.find( |
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This will only catch one value instead of all values that are incorrect. Given that .find will loop through all parameters if there is no invalid element it's likely better to collect all of them
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@timneutkens
Good point! Updated to use filter() to collect all invalid elements instead of just the first one.
The error message now shows all invalid values.
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What?
Improve error messages when non-string values are passed to
getStaticPathsorgenerateStaticParams.Why?
When developers accidentally pass non-string values (e.g., numbers) to path parameters, the current error message is cryptic:
This makes debugging difficult, especially for beginners.
How?
escapePathDelimiters()function to check if the segment is a stringpages.tsfor catch-all routes ([...slug])app.tsforgenerateStaticParamsNow the error message is clear:
Testing
escapePathDelimiterswith invalid inputspnpm test-unit)fixes #41281