refactor(cz-commitlint): remove duplication in case conversion

The cz-commitlint was previously duplicating the case conversion logic also found in the
@commitlint/ensure package.

Author: hasghari

@commitlint/cz-commitlint/package.json

@@ -36,6 +36,7 @@
     }
   },
   "dependencies": {
+    "@commitlint/ensure": "^13.2.0",
     "@commitlint/load": "^13.2.1",
     "@commitlint/types": "^13.2.0",
     "chalk": "^4.1.0",

@commitlint/cz-commitlint/src/utils/case-fn.test.ts

@@ -32,13 +32,11 @@ test('should not apply', () => {
 });
 
 test('should throw error on invalid casing', () => {
-	expect(() => getCaseFn([RuleConfigSeverity.Warning, 'always'])).toThrow(
-		'Unknown target case "undefined"'
-	);
+	let rule = getCaseFn([RuleConfigSeverity.Warning, 'always']);
+	expect(() => rule('test')).toThrow('Unknown target case "undefined"');
 
-	expect(() =>
-		getCaseFn([RuleConfigSeverity.Warning, 'always', 'foo'])
-	).toThrow('Unknown target case "foo"');
+	rule = getCaseFn([RuleConfigSeverity.Warning, 'always', 'foo']);
+	expect(() => rule('test')).toThrow('Unknown target case "foo"');
 });
 
 test('should convert text correctly', () => {

@commitlint/cz-commitlint/src/utils/case-fn.ts

@@ -1,8 +1,5 @@
-import camelCase from 'lodash/camelCase';
-import kebabCase from 'lodash/kebabCase';
-import snakeCase from 'lodash/snakeCase';
-import startCase from 'lodash/startCase';
-import upperFirst from 'lodash/upperFirst';
+import {toCase} from '@commitlint/ensure';
+import {TargetCaseType} from '@commitlint/types';
 import {Rule} from '../types';
 import {ruleIsActive, ruleIsNotApplicable} from './rules';
 
@@ -26,28 +23,5 @@ export default function getCaseFn(rule?: Rule): CaseFn {
 		return noop;
 	}
 
-	switch (target) {
-		case 'camel-case':
-			return (input: string) => camelCase(input);
-		case 'kebab-case':
-			return (input: string) => kebabCase(input);
-		case 'snake-case':
-			return (input: string) => snakeCase(input);
-		case 'pascal-case':
-			return (input: string) => upperFirst(camelCase(input));
-		case 'start-case':
-			return (input: string) => startCase(input);
-		case 'upper-case':
-		case 'uppercase':
-			return (input: string) => input.toUpperCase();
-		case 'sentence-case':
-		case 'sentencecase':
-			return (input: string) => upperFirst(input);
-		case 'lower-case':
-		case 'lowercase':
-		case 'lowerCase': // Backwards compat config-angular v4
-			return (input: string) => input.toLowerCase();
-		default:
-			throw new TypeError(`Unknown target case "${target}"`);
-	}
+	return (input: string) => toCase(input, target as TargetCaseType);
 }

@commitlint/ensure/src/case.ts

@@ -1,8 +1,4 @@
-import camelCase from 'lodash/camelCase';
-import kebabCase from 'lodash/kebabCase';
-import snakeCase from 'lodash/snakeCase';
-import upperFirst from 'lodash/upperFirst';
-import startCase from 'lodash/startCase';
+import toCase from './to-case';
 import {TargetCaseType} from '@commitlint/types';
 
 export default ensureCase;
@@ -25,30 +21,3 @@ function ensureCase(
 
 	return transformed === input;
 }
-
-function toCase(input: string, target: TargetCaseType): string {
-	switch (target) {
-		case 'camel-case':
-			return camelCase(input);
-		case 'kebab-case':
-			return kebabCase(input);
-		case 'snake-case':
-			return snakeCase(input);
-		case 'pascal-case':
-			return upperFirst(camelCase(input));
-		case 'start-case':
-			return startCase(input);
-		case 'upper-case':
-		case 'uppercase':
-			return input.toUpperCase();
-		case 'sentence-case':
-		case 'sentencecase':
-			return upperFirst(input);
-		case 'lower-case':
-		case 'lowercase':
-		case 'lowerCase': // Backwards compat config-angular v4
-			return input.toLowerCase();
-		default:
-			throw new TypeError(`ensure-case: Unknown target case "${target}"`);
-	}
-}

@commitlint/ensure/src/index.ts

@@ -4,7 +4,8 @@ import maxLength from './max-length';
 import maxLineLength from './max-line-length';
 import minLength from './min-length';
 import notEmpty from './not-empty';
+import toCase from './to-case';
 
 export {ensureCase as case};
 export {ensureEnum as enum};
-export {maxLength, maxLineLength, minLength, notEmpty};
+export {maxLength, maxLineLength, minLength, notEmpty, toCase};

@commitlint/ensure/src/to-case.ts

@@ -0,0 +1,33 @@
+import {TargetCaseType} from '@commitlint/types';
+import camelCase from 'lodash/camelCase';
+import kebabCase from 'lodash/kebabCase';
+import snakeCase from 'lodash/snakeCase';
+import upperFirst from 'lodash/upperFirst';
+import startCase from 'lodash/startCase';
+
+export default function toCase(input: string, target: TargetCaseType): string {
+	switch (target) {
+		case 'camel-case':
+			return camelCase(input);
+		case 'kebab-case':
+			return kebabCase(input);
+		case 'snake-case':
+			return snakeCase(input);
+		case 'pascal-case':
+			return upperFirst(camelCase(input));
+		case 'start-case':
+			return startCase(input);
+		case 'upper-case':
+		case 'uppercase':
+			return input.toUpperCase();
+		case 'sentence-case':
+		case 'sentencecase':
+			return upperFirst(input);
+		case 'lower-case':
+		case 'lowercase':
+		case 'lowerCase': // Backwards compat config-angular v4
+			return input.toLowerCase();
+		default:
+			throw new TypeError(`to-case: Unknown target case "${target}"`);
+	}
+}