feat: add lowercase to key-format-style rule

Author: oikalyptus

lib/rules/key-format-style.ts

@@ -16,6 +16,7 @@ const debug = debugBuilder('eslint-plugin-vue-i18n:key-format-style')
 const allowedCaseOptions = [
   'camelCase',
   'kebab-case',
+  'lowercase',
   'snake_case',
   'SCREAMING_SNAKE_CASE'
 ] as const

lib/utils/casing.ts

@@ -75,6 +75,20 @@ export function isCamelCase(str: string): boolean {
   return true
 }
 
+/**
+ * Checks whether the given string is lowercase.
+ */
+export function isLowerCase(str: string): boolean {
+  if (
+    hasSymbols(str) ||
+    hasUpper(str) ||
+    /-|_|\s/u.exec(str) // kebab or snake or space
+  ) {
+    return false
+  }
+  return true
+}
+
 /**
  * Checks whether the given string is PascalCase.
  */
@@ -104,6 +118,7 @@ const checkersMap = {
   'kebab-case': isKebabCase,
   snake_case: isSnakeCase,
   camelCase: isCamelCase,
+  lowercase: isLowerCase,
   PascalCase: isPascalCase,
   SCREAMING_SNAKE_CASE: isScreamingSnakeCase
 }
@@ -127,6 +142,7 @@ export function pascalCase(str: string): string {
 export const allowedCaseOptions = [
   'camelCase',
   'kebab-case',
+  'lowercase',
   'PascalCase',
   'snake_case',
   'SCREAMING_SNAKE_CASE'

tests/lib/rules/key-format-style.ts

@@ -129,6 +129,41 @@ tester.run('key-format-style', rule as never, {
       ...options.json.file,
       options: ['kebab-case']
     },
+    {
+      code: `
+      lowercase:
+        foobar: kebab-value
+      `,
+      ...options.yaml.file
+    },
+    {
+      code: `{
+        "lowercase": {
+          "foobar": "kebab-value"
+        }
+      }
+      `,
+      ...options.json.file
+    },
+    {
+      code: `
+      en-US:
+        lowercase:
+          foobar: kebab-value
+      `,
+      ...options.yaml.key
+    },
+    {
+      code: `{
+        "en-US": {
+          "lowercase": {
+            "foobar": "kebab-value"
+          }
+        }
+      }
+      `,
+      ...options.json.key
+    },
     {
       code: `
       snake_case:
@@ -379,6 +414,136 @@ tester.run('key-format-style', rule as never, {
         }
       ]
     },
+    {
+      code: `
+      foo-bar: baz
+      `,
+      ...options.yaml.file,
+      options: ['lowercase'],
+      errors: [
+        {
+          message: '"foo-bar" is not lowercase',
+          line: 2
+        }
+      ]
+    },
+    {
+      code: `
+      en-US:
+        foo-bar: baz
+      `,
+      ...options.yaml.key,
+      options: ['lowercase'],
+      errors: [
+        {
+          message: '"foo-bar" is not lowercase',
+          line: 3
+        }
+      ]
+    },
+    {
+      code: `
+      {"foo-bar": "baz"}
+      `,
+      ...options.json.file,
+      options: ['lowercase'],
+      errors: [
+        {
+          message: '"foo-bar" is not lowercase',
+          line: 2
+        }
+      ]
+    },
+    {
+      code: `
+      {"en-US": {
+        "foo-bar": "baz"
+      }}`,
+      ...options.json.key,
+      options: ['lowercase'],
+      errors: [
+        {
+          message: '"foo-bar" is not lowercase',
+          line: 3
+        }
+      ]
+    },
+    {
+      code: `
+      kebab-case:
+        snake_case: camelCase
+      `,
+      ...options.yaml.file,
+      options: ['lowercase'],
+      errors: [
+        {
+          message: '"kebab-case" is not lowercase',
+          line: 2
+        },
+        {
+          message: '"snake_case" is not lowercase',
+          line: 3
+        }
+      ]
+    },
+    {
+      code: `{
+        "kebab-case": {
+          "snake_case": "camelCase"
+        }
+      }
+      `,
+      ...options.json.file,
+      options: ['lowercase'],
+      errors: [
+        {
+          message: '"kebab-case" is not lowercase',
+          line: 2
+        },
+        {
+          message: '"snake_case" is not lowercase',
+          line: 3
+        }
+      ]
+    },
+    {
+      code: `
+      SCREAMING_SNAKE_CASE:
+        PascalCase: camelCase
+      `,
+      ...options.yaml.file,
+      options: ['lowercase'],
+      errors: [
+        {
+          message: '"SCREAMING_SNAKE_CASE" is not lowercase',
+          line: 2
+        },
+        {
+          message: '"PascalCase" is not lowercase',
+          line: 3
+        }
+      ]
+    },
+    {
+      code: `{
+        "SCREAMING_SNAKE_CASE": {
+          "PascalCase": "camelCase"
+        }
+      }
+      `,
+      ...options.json.file,
+      options: ['lowercase'],
+      errors: [
+        {
+          message: '"SCREAMING_SNAKE_CASE" is not lowercase',
+          line: 2
+        },
+        {
+          message: '"PascalCase" is not lowercase',
+          line: 3
+        }
+      ]
+    },
     {
       code: `
       - foo