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fix(eslint-plugin): [switch-exhaustiveness-check] enum members with n…
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…ew line or single quotes are not being fixed correctly (#7806)

* feat(eslint-plugin): [switch-exhaustiveness-check] members with new line or single quotes are not being fixed correctly

Closes #7768

* cleanup

* oops

* wip wip

* maybe?

* idk why it was missing
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@StyleShit
StyleShit committed Nov 16, 2023
1 parent c65b9dd commit a034d0a
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94 changes: 86 additions & 8 deletions packages/eslint-plugin/docs/rules/switch-exhaustiveness-check.md
View file
@@ -1,18 +1,22 @@
---
description: 'Require switch-case statements to be exhaustive with union type.'
description: 'Require switch-case statements to be exhaustive with union types and enums.'
---

> 🛑 This file is source code, not the primary documentation location! 🛑
>
> See **https://typescript-eslint.io/rules/switch-exhaustiveness-check** for documentation.
When working with union types in TypeScript, it's common to want to write a `switch` statement intended to contain a `case` for each constituent (possible type in the union).
However, if the union type changes, it's easy to forget to modify the cases to account for any new types.
When working with union types or enums in TypeScript, it's common to want to write a `switch` statement intended to contain a `case` for each constituent (possible type in the union or the enum).
However, if the union type or the enum changes, it's easy to forget to modify the cases to account for any new types.

This rule reports when a `switch` statement over a value typed as a union of literals is missing a case for any of those literal types and does not have a `default` clause.
This rule reports when a `switch` statement over a value typed as a union of literals or as an enum is missing a case for any of those literal types and does not have a `default` clause.

## Examples

When the switch doesn't have exhaustive cases, either filling them all out or adding a default will correct the rule's complaint.

Here are some examples of code working with a union of literals:

<!--tabs-->

### ❌ Incorrect
Expand All @@ -27,7 +31,7 @@ type Day =
| 'Saturday'
| 'Sunday';

const day = 'Monday' as Day;
declare const day: Day;
let result = 0;

switch (day) {
Expand All @@ -49,7 +53,7 @@ type Day =
| 'Saturday'
| 'Sunday';

const day = 'Monday' as Day;
declare const day: Day;
let result = 0;

switch (day) {
Expand Down Expand Up @@ -89,7 +93,7 @@ type Day =
| 'Saturday'
| 'Sunday';

const day = 'Monday' as Day;
declare const day: Day;
let result = 0;

switch (day) {
Expand All @@ -101,6 +105,80 @@ switch (day) {
}
```

<!--/tabs-->

Likewise, here are some examples of code working with an enum:

<!--tabs-->

### ❌ Incorrect

```ts
enum Fruit {
Apple,
Banana,
Cherry,
}

declare const fruit: Fruit;

switch (fruit) {
case Fruit.Apple:
console.log('an apple');
break;
}
```

### ✅ Correct

```ts
enum Fruit {
Apple,
Banana,
Cherry,
}

declare const fruit: Fruit;

switch (fruit) {
case Fruit.Apple:
console.log('an apple');
break;

case Fruit.Banana:
console.log('a banana');
break;

case Fruit.Cherry:
console.log('a cherry');
break;
}
```

### ✅ Correct

```ts
enum Fruit {
Apple,
Banana,
Cherry,
}

declare const fruit: Fruit;

switch (fruit) {
case Fruit.Apple:
console.log('an apple');
break;

default:
console.log('a fruit');
break;
}
```

<!--/tabs-->

## When Not To Use It

If you don't frequently `switch` over union types with many parts, or intentionally wish to leave out some parts.
If you don't frequently `switch` over union types or enums with many parts, or intentionally wish to leave out some parts.
12 changes: 9 additions & 3 deletions packages/eslint-plugin/src/rules/switch-exhaustiveness-check.ts
View file
Expand Up @@ -18,7 +18,7 @@ export default createRule({
type: 'suggestion',
docs: {
description:
'Require switch-case statements to be exhaustive with union type',
'Require switch-case statements to be exhaustive with union types and enums',
requiresTypeChecking: true,
},
hasSuggestions: true,
Expand Down Expand Up @@ -74,13 +74,19 @@ export default createRule({
(missingBranchName || missingBranchName === '') &&
requiresQuoting(missingBranchName.toString(), compilerOptions.target)
) {
caseTest = `${symbolName}['${missingBranchName}']`;
const escapedBranchName = missingBranchName
.replace(/'/g, "\\'")
.replace(/\n/g, '\\n')
.replace(/\r/g, '\\r');

caseTest = `${symbolName}['${escapedBranchName}']`;
}

const errorMessage = `Not implemented yet: ${caseTest} case`;
const escapedErrorMessage = errorMessage.replace(/'/g, "\\'");

missingCases.push(
`case ${caseTest}: { throw new Error('${errorMessage}') }`,
`case ${caseTest}: { throw new Error('${escapedErrorMessage}') }`,
);
}

Expand Down
83 changes: 79 additions & 4 deletions packages/eslint-plugin/tests/rules/switch-exhaustiveness-check.test.ts
View file
@@ -1,4 +1,4 @@
import { RuleTester } from '@typescript-eslint/rule-tester';
import { noFormat, RuleTester } from '@typescript-eslint/rule-tester';
import path from 'path';

import switchExhaustivenessCheck from '../../src/rules/switch-exhaustiveness-check';
Expand Down Expand Up @@ -518,7 +518,7 @@ export enum Enum {
function test(arg: Enum): string {
switch (arg) {
case Enum['test-test']: { throw new Error('Not implemented yet: Enum['test-test'] case') }
case Enum['test-test']: { throw new Error('Not implemented yet: Enum[\\'test-test\\'] case') }
case Enum.test: { throw new Error('Not implemented yet: Enum.test case') }
}
}
Expand Down Expand Up @@ -555,7 +555,7 @@ export enum Enum {
function test(arg: Enum): string {
switch (arg) {
case Enum['']: { throw new Error('Not implemented yet: Enum[''] case') }
case Enum['']: { throw new Error('Not implemented yet: Enum[\\'\\'] case') }
case Enum.test: { throw new Error('Not implemented yet: Enum.test case') }
}
}
Expand Down Expand Up @@ -592,7 +592,7 @@ export enum Enum {
function test(arg: Enum): string {
switch (arg) {
case Enum['9test']: { throw new Error('Not implemented yet: Enum['9test'] case') }
case Enum['9test']: { throw new Error('Not implemented yet: Enum[\\'9test\\'] case') }
case Enum.test: { throw new Error('Not implemented yet: Enum.test case') }
}
}
Expand All @@ -602,5 +602,80 @@ function test(arg: Enum): string {
},
],
},
{
code: `
enum Enum {
'a' = 1,
[\`key-with
new-line\`] = 2,
}
declare const a: Enum;
switch (a) {
}
`,
errors: [
{
messageId: 'switchIsNotExhaustive',
suggestions: [
{
messageId: 'addMissingCases',
output: `
enum Enum {
'a' = 1,
[\`key-with
new-line\`] = 2,
}
declare const a: Enum;
switch (a) {
case Enum.a: { throw new Error('Not implemented yet: Enum.a case') }
case Enum['key-with\\n\\n new-line']: { throw new Error('Not implemented yet: Enum[\\'key-with\\n\\n new-line\\'] case') }
}
`,
},
],
},
],
},
{
code: noFormat`
enum Enum {
'a' = 1,
"'a' \`b\` \\"c\\"" = 2,
}
declare const a: Enum;
switch (a) {}
`,
errors: [
{
messageId: 'switchIsNotExhaustive',
suggestions: [
{
messageId: 'addMissingCases',
output: `
enum Enum {
'a' = 1,
"'a' \`b\` \\"c\\"" = 2,
}
declare const a: Enum;
switch (a) {
case Enum.a: { throw new Error('Not implemented yet: Enum.a case') }
case Enum['\\'a\\' \`b\` "c"']: { throw new Error('Not implemented yet: Enum[\\'\\\\'a\\\\' \`b\` "c"\\'] case') }
}
`,
},
],
},
],
},
],
});

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