chore: lint custom ts/no-arrow-parameter-types

[Shinigami92]

No description provided.

[github-actions]

Coverage Report

Status	Category	Percentage	Covered / Total
🔵	Lines	93.39% (🎯 90%) ⬆️ +0.06%	1456 / 1559
🔵	Statements	93.4% (🎯 90%) 🟰 ±0%	1474 / 1578
🔵	Functions	94.73% (🎯 90%) 🟰 ±0%	324 / 342
🔵	Branches	87.22% (🎯 85%) 🟰 ±0%	935 / 1072

File Coverage

File	Stmts	Branches	Functions	Lines	Uncovered Lines
Changed Files
src/db.ts	78.43% 🟰 ±0%	75% 🟰 ±0%	76.92% 🟰 ±0%	78% 🟰 ±0%	90-92, 125-137, 176, 180-181
src/migrationBuilder.ts	95.49% 🟰 ±0%	62.5% 🟰 ±0%	90% 🟰 ±0%	95.49% 🟰 ±0%	835-838, 980-984
src/operations/operators/addToOperatorFamily.ts	100% 🟰 ±0%	100% 🟰 ±0%	100% 🟰 ±0%	100% 🟰 ±0%
src/operations/operators/removeFromOperatorFamily.ts	100% 🟰 ±0%	100% 🟰 ±0%	100% 🟰 ±0%	100% 🟰 ±0%
src/operations/schemas/createSchema.ts	100% 🟰 ±0%	100% 🟰 ±0%	100% 🟰 ±0%	100% 🟰 ±0%
src/operations/tables/shared.ts	86.79% 🟰 ±0%	76.76% 🟰 ±0%	76.47% 🟰 ±0%	87.61% ⬆️ +0.82%	157, 241, 261, 287, 291-297, 301, 445-463
src/operations/triggers/createTrigger.ts	88.23% 🟰 ±0%	71.79% 🟰 ±0%	100% 🟰 ±0%	88.23% 🟰 ±0%	55, 68, 72, 76-78
Unchanged Files
src/index.ts	100%	100%	100%	100%
src/logger.ts	100%	100%	100%	100%
src/migration.ts	79.66%	74.07%	79.16%	79.48%	149-151, 174-187, 235-236, 301-336, 402, 429-431, 439, 457-459, 489
src/migrationOptions.ts	100%	100%	100%	100%
src/pgType.ts	100%	100%	100%	100%
src/runner.ts	76.85%	60.56%	82.6%	76.06%	209-217, 230, 283, 328, 338-341, 355, 367-369, 393, 434-445, 450-452, 473-474, 484, 486-494
src/sqlMigration.ts	83.33%	100%	80%	83.33%	57-59
src/operations/sql.ts	100%	50%	100%	100%
src/operations/casts/createCast.ts	100%	100%	100%	100%
src/operations/casts/dropCast.ts	100%	100%	100%	100%
src/operations/casts/index.ts	100%	100%	100%	100%
src/operations/domains/alterDomain.ts	100%	100%	100%	100%
src/operations/domains/createDomain.ts	100%	95.45%	100%	100%
src/operations/domains/dropDomain.ts	100%	100%	100%	100%
src/operations/domains/index.ts	100%	100%	100%	100%
src/operations/domains/renameDomain.ts	100%	100%	100%	100%
src/operations/domains/shared.ts	100%	100%	100%	100%
src/operations/extensions/createExtension.ts	100%	100%	100%	100%
src/operations/extensions/dropExtension.ts	100%	100%	100%	100%
src/operations/extensions/index.ts	100%	100%	100%	100%
src/operations/extensions/shared.ts	100%	100%	100%	100%
src/operations/functions/createFunction.ts	96.29%	92%	100%	96.29%	71-73
src/operations/functions/dropFunction.ts	100%	100%	100%	100%
src/operations/functions/index.ts	100%	100%	100%	100%
src/operations/functions/renameFunction.ts	100%	100%	100%	100%
src/operations/functions/shared.ts	100%	100%	100%	100%
src/operations/grants/grantOnSchemas.ts	100%	100%	100%	100%
src/operations/grants/grantOnTables.ts	100%	100%	100%	100%
src/operations/grants/grantRoles.ts	100%	100%	100%	100%
src/operations/grants/index.ts	100%	100%	100%	100%
src/operations/grants/revokeOnSchemas.ts	100%	100%	100%	100%
src/operations/grants/revokeOnTables.ts	100%	100%	100%	100%
src/operations/grants/revokeRoles.ts	100%	100%	100%	100%
src/operations/grants/shared.ts	100%	75%	100%	100%
src/operations/indexes/createIndex.ts	100%	100%	100%	100%
src/operations/indexes/dropIndex.ts	100%	100%	100%	100%
src/operations/indexes/index.ts	100%	100%	100%	100%
src/operations/indexes/shared.ts	100%	88.23%	100%	100%
src/operations/materializedViews/alterMaterializedView.ts	100%	100%	100%	100%
src/operations/materializedViews/createMaterializedView.ts	100%	100%	100%	100%
src/operations/materializedViews/dropMaterializedView.ts	100%	100%	100%	100%
src/operations/materializedViews/index.ts	100%	100%	100%	100%
src/operations/materializedViews/refreshMaterializedView.ts	100%	100%	100%	100%
src/operations/materializedViews/renameMaterializedView.ts	100%	100%	100%	100%
src/operations/materializedViews/renameMaterializedViewColumn.ts	100%	100%	100%	100%
src/operations/materializedViews/shared.ts	100%	83.33%	100%	100%
src/operations/operators/createOperator.ts	100%	88.88%	100%	100%
src/operations/operators/createOperatorClass.ts	100%	75%	100%	100%
src/operations/operators/createOperatorFamily.ts	100%	100%	100%	100%
src/operations/operators/dropOperator.ts	100%	100%	100%	100%
src/operations/operators/dropOperatorClass.ts	100%	100%	100%	100%
src/operations/operators/dropOperatorFamily.ts	100%	100%	100%	100%
src/operations/operators/index.ts	100%	100%	100%	100%
src/operations/operators/renameOperatorClass.ts	100%	100%	100%	100%
src/operations/operators/renameOperatorFamily.ts	100%	100%	100%	100%
src/operations/operators/shared.ts	81.81%	77.77%	100%	81.81%	24, 38
src/operations/policies/alterPolicy.ts	100%	100%	100%	100%
src/operations/policies/createPolicy.ts	100%	100%	100%	100%
src/operations/policies/dropPolicy.ts	100%	100%	100%	100%
src/operations/policies/index.ts	100%	100%	100%	100%
src/operations/policies/renamePolicy.ts	100%	100%	100%	100%
src/operations/policies/shared.ts	100%	100%	100%	100%
src/operations/roles/alterRole.ts	100%	100%	100%	100%
src/operations/roles/createRole.ts	100%	92.3%	100%	100%
src/operations/roles/dropRole.ts	100%	100%	100%	100%
src/operations/roles/index.ts	100%	100%	100%	100%
src/operations/roles/renameRole.ts	100%	100%	100%	100%
src/operations/roles/shared.ts	100%	86.66%	100%	100%
src/operations/schemas/dropSchema.ts	100%	100%	100%	100%
src/operations/schemas/index.ts	100%	100%	100%	100%
src/operations/schemas/renameSchema.ts	100%	100%	100%	100%
src/operations/sequences/alterSequence.ts	90%	83.33%	100%	90%	23
src/operations/sequences/createSequence.ts	100%	100%	100%	100%
src/operations/sequences/dropSequence.ts	100%	100%	100%	100%
src/operations/sequences/index.ts	100%	100%	100%	100%
src/operations/sequences/renameSequence.ts	100%	100%	100%	100%
src/operations/sequences/shared.ts	81.48%	83.33%	100%	81.48%	41, 43, 49, 63, 69
src/operations/tables/addColumns.ts	100%	85.71%	100%	100%
src/operations/tables/addConstraint.ts	100%	100%	100%	100%
src/operations/tables/alterColumn.ts	91.17%	81.25%	100%	91.17%	69, 76-83
src/operations/tables/alterTable.ts	100%	100%	100%	100%
src/operations/tables/createTable.ts	88%	82.14%	100%	88%	51-54, 92
src/operations/tables/dropColumns.ts	100%	100%	100%	100%
src/operations/tables/dropConstraint.ts	100%	100%	100%	100%
src/operations/tables/dropTable.ts	100%	100%	100%	100%
src/operations/tables/index.ts	100%	100%	100%	100%
src/operations/tables/renameColumn.ts	100%	100%	100%	100%
src/operations/tables/renameConstraint.ts	100%	100%	100%	100%
src/operations/tables/renameTable.ts	100%	100%	100%	100%
src/operations/triggers/dropTrigger.ts	100%	100%	100%	100%
src/operations/triggers/index.ts	100%	100%	100%	100%
src/operations/triggers/renameTrigger.ts	100%	100%	100%	100%
src/operations/triggers/shared.ts	100%	100%	100%	100%
src/operations/types/addTypeAttribute.ts	100%	100%	100%	100%
src/operations/types/addTypeValue.ts	100%	100%	100%	100%
src/operations/types/createType.ts	100%	100%	100%	100%
src/operations/types/dropType.ts	100%	100%	100%	100%
src/operations/types/dropTypeAttribute.ts	100%	100%	100%	100%
src/operations/types/index.ts	100%	100%	100%	100%
src/operations/types/renameType.ts	100%	100%	100%	100%
src/operations/types/renameTypeAttribute.ts	100%	100%	100%	100%
src/operations/types/renameTypeValue.ts	100%	100%	100%	100%
src/operations/types/setTypeAttribute.ts	100%	100%	100%	100%
src/operations/views/alterView.ts	100%	100%	100%	100%
src/operations/views/alterViewColumn.ts	100%	100%	100%	100%
src/operations/views/createView.ts	100%	100%	100%	100%
src/operations/views/dropView.ts	100%	100%	100%	100%
src/operations/views/index.ts	100%	100%	100%	100%
src/operations/views/renameView.ts	100%	100%	100%	100%
src/operations/views/shared.ts	100%	50%	100%	100%
src/utils/PgLiteral.ts	100%	100%	100%	100%
src/utils/createSchemalize.ts	96.42%	93.54%	100%	96.29%	84
src/utils/createTransformer.ts	100%	100%	100%	100%
src/utils/decamelize.ts	100%	100%	100%	100%
src/utils/escapeValue.ts	100%	100%	100%	100%
src/utils/formatLines.ts	100%	100%	100%	100%
src/utils/formatParams.ts	100%	87.5%	100%	100%
src/utils/formatPartitionColumns.ts	100%	100%	100%	100%
src/utils/getMigrationTableSchema.ts	100%	100%	100%	100%
src/utils/getSchemas.ts	100%	100%	100%	100%
src/utils/identity.ts	100%	100%	100%	100%
src/utils/index.ts	100%	100%	100%	100%
src/utils/intersection.ts	100%	100%	100%	100%
src/utils/makeComment.ts	100%	100%	100%	100%
src/utils/quote.ts	100%	100%	100%	100%
src/utils/stringIdGenerator.ts	100%	100%	100%	100%
src/utils/toArray.ts	100%	100%	100%	100%
src/utils/types.ts	100%	100%	100%	100%

Generated in workflow #3030 for commit 9d2bb6c by the Vitest Coverage Report Action

[Shinigami92]

@bradzacher @JoshuaKGoldberg Hey typescript-lint maintainers.

I'm currently working again with many trainees in my company work. There I have the issue that they write a lot code like e.g.:

const someElements = getElements()
//    ^? = any[]

someElements.filter((element: Element) => element.needed)
//                          ~~~~~~~~~ <- I don't want these arrow-parameter types

This is all over the codebase in multiple projects. (I'm new in that company)
Now I would like to create an eslint rule that explains trainees that they should think about what they are typing and where.
So instead of adding a type annotation in every arrow-callback function, they should add a type annotation to the variable or return-type.

e.g.

function getElements(): Element[] { return [] }
// or
const someElements: Element[] = getElements()

someElements.filter((element) => element.needed)
//                   ~~~~~~~ <- now gets inferred as Element 🎉 

So my question to you typescript-lint maintainers is: Are you interested in such a rule proposal?
I would battle-test it in some more repos first and next week at work.
Or is there something fundamentally that speaks against using such a rule in typescript-lint?

[JoshuaKGoldberg]

Are you interested in such a rule proposal?

I'd say in general the right next step would be to file an issue asking this in typescript-eslint. Even if the idea isn't something that lands in core, that'd give it more visibility. If you end up writing your own custom plugin that'd be a good place to mention it.

Though...

// ^? = any[]

This seems like the root problem, no? That folks are having anys in places? We generally don't add a lot of rules for situations that boil down to "there's an any and now other things are unsafe".

Also: typescript-eslint/typescript-eslint#2673 is another example of why these kinds of rules can be surprisingly difficult to write.