fix(prompt): apply forced cases properly

closes #145

@commitlint/prompt/src/library/get-forced-case-fn.js

@@ -1,4 +1,4 @@
-import getForcedCase from './get-forced-case';
+import {camelCase, kebabCase, snakeCase, upperFirst, startCase} from 'lodash';
 
 /**
  * Get forced case for rule
@@ -7,18 +7,58 @@ import getForcedCase from './get-forced-case';
  */
 export default function getForcedCaseFn(rule) {
 	const noop = input => input;
-	const lowerCase = input => String.prototype.toLowerCase.call(input);
-	const upperCase = input => String.prototype.toUpperCase.call(input);
 
 	if (!rule) {
 		return noop;
 	}
 
-	const forcedCase = getForcedCase(rule);
+	const [config] = rule;
 
-	if (forcedCase === null) {
+	if (!Array.isArray(config)) {
 		return noop;
 	}
 
-	return forcedCase === 'lowerCase' ? lowerCase : upperCase;
+	const [level] = config;
+
+	if (level === 0) {
+		return;
+	}
+
+	const [, when] = config;
+
+	if (when === 'neve') {
+		return;
+	}
+
+	const [, , target] = config;
+
+	if (Array.isArray(target)) {
+		return noop;
+	}
+
+	switch (target) {
+		case 'camel-case':
+			return input => camelCase(input);
+		case 'kebab-case':
+			return input => kebabCase(input);
+		case 'snake-case':
+			return input => snakeCase(input);
+		case 'pascal-case':
+			return input => upperFirst(camelCase(input));
+		case 'start-case':
+			return input => startCase(input);
+		case 'upper-case':
+		case 'uppercase':
+			return input => input.toUpperCase();
+		case 'sentence-case':
+		case 'sentencecase':
+			return input =>
+				`${input.charAt(0).toUpperCase()}${input.substring(1).toLowerCase()}`;
+		case 'lower-case':
+		case 'lowercase':
+		case 'lowerCase': // Backwards compat config-angular v4
+			return input => input.toLowerCase() === input;
+		default:
+			throw new TypeError(`Unknown target case "${rule[2]}"`);
+	}
 }

@commitlint/prompt/src/library/get-prompt.js

@@ -2,7 +2,6 @@ import chalk from 'chalk';
 
 import enumRuleIsActive from './enum-rule-is-active';
 import format from './format';
-import getForcedCase from './get-forced-case';
 import getForcedCaseFn from './get-forced-case-fn';
 import getForcedLeadingFn from './get-forced-leading-fn';
 import getHasName from './get-has-name';
@@ -78,7 +77,6 @@ function getPrompt(type, context = {}) {
 
 	const caseRule = rules.filter(getHasName('case'))[0];
 
-	const forcedCase = getForcedCase(caseRule);
 	const forceCaseFn = getForcedCaseFn(caseRule);
 
 	const leadingBlankRule = rules.filter(getHasName('leading-blank'))[0];
@@ -219,7 +217,6 @@ function getPrompt(type, context = {}) {
 				required: mayNotBeEmpty,
 				'tab-completion': typeof enumRule !== 'undefined',
 				header: typeof settings.header !== 'undefined',
-				case: forcedCase,
 				'multi-line': settings.multiline
 			})}`
 		);