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Search Terms: error message pretty collapsing
The TS team started a few conversations in TSConf 2018 about making TypeScript error messages more friendly to newcomers. One good first one to approach could be repeated, near-identical errors around the same type.
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For example, if a type is missing multiple times in the same file:
let a: MissingType;
let b: MissingType;
// ..
let c: MissingType;
Expected behavior:
In a debatably perfect world, TypeScript could give a single error message for the repeated class of error:
src/index.ts Error TS2304: Cannot find name 'MissingType'.
1 let a: MissingType;
~~~~~~~~~~~
2 let b: MissingType;
~~~~~~~~~~~
4 let c: MissingType;
~~~~~~~~~~~
Actual behavior:
Three separate errors.
Perhaps a post-processing step in --pretty
mode that receives all of a file's errors and smooshes them down when it can?
Some open questions:
- Which classes of errors would be in this bucket?
- Example: TS2304 missing type if the type is the same
- Example: TS2339 property does not exist if the type and property are the same
- How should this look?
- As suggested above, which is similar to existing
--pretty
output but with line+column removed? - If there are a many of the same error, should the output truncate with a summary?
- As suggested above, which is similar to existing
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DanielRosenwasser commentedon Apr 13, 2018
DanielRosenwasser commentedon Apr 13, 2018
#10489 and #22789 both discuss the idea of related spans which could be leveraged here, but you really want to cut down on these. We could defer all "cannot find" error messages to the end of the checking process and potentially de-dupe in that fashion.
The problem is that you really want to still present the related spans outside of
pretty
, so we'd need to report a different error depending onpretty
which feels bad-ish.RyanCavanaugh commentedon Apr 17, 2018
Revisit once we have general multi-location diagnostic support.
Some notes in #23444
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