refactor: abstract lintoutcome construction

@commitlint/lint/src/lint-outcome.ts

@@ -0,0 +1,56 @@
+import {
+	LintOutcome as LintOutcomeData,
+	LintRuleOutcome,
+	Commit
+} from '@commitlint/types';
+import {buildCommitMesage} from './commit-message';
+
+export interface EmptyInit {
+	message: string;
+}
+
+export interface ResultsInit {
+	parsed: Commit;
+	results: LintRuleOutcome[];
+}
+
+export class LintOutcome implements LintOutcomeData {
+	public readonly input: string;
+	public readonly valid: boolean;
+	public readonly errors: LintRuleOutcome[];
+	public readonly warnings: LintRuleOutcome[];
+
+	public static empty(init: EmptyInit): LintOutcome {
+		return new LintOutcome({
+			valid: true,
+			errors: [],
+			warnings: [],
+			input: init.message
+		});
+	}
+
+	public static fromResults(init: ResultsInit): LintOutcome {
+		const errors = init.results.filter(
+			result => result.level === 2 && !result.valid
+		);
+		const warnings = init.results.filter(
+			result => result.level === 1 && !result.valid
+		);
+
+		const valid = errors.length === 0;
+
+		return {
+			valid,
+			errors,
+			warnings,
+			input: buildCommitMesage(init.parsed)
+		};
+	}
+
+	private constructor(init: LintOutcomeData) {
+		this.input = init.input;
+		this.valid = init.valid;
+		this.errors = init.errors;
+		this.warnings = init.warnings;
+	}
+}

@commitlint/lint/src/lint.ts

@@ -2,16 +2,14 @@ import util from 'util';
 import isIgnored from '@commitlint/is-ignored';
 import parse from '@commitlint/parse';
 import defaultRules from '@commitlint/rules';
-import toPairs from 'lodash/toPairs';
-import {buildCommitMesage} from './commit-message';
 import {
 	LintRuleConfig,
 	LintOptions,
 	LintRuleOutcome,
 	Rule,
-	RuleSeverity,
-	LintOutcome
+	RuleSeverity
 } from '@commitlint/types';
+import {LintOutcome} from './lint-outcome';
 
 export default async function lint(
 	message: string,
@@ -27,28 +25,19 @@ export default async function lint(
 	if (
 		isIgnored(message, {defaults: opts.defaultIgnores, ignores: opts.ignores})
 	) {
-		return {
-			valid: true,
-			errors: [],
-			warnings: [],
-			input: message
-		};
+		return LintOutcome.empty({message});
 	}
 
 	// Parse the commit message
 	const parsed = await parse(message, undefined, opts.parserOpts);
+
 	if (
 		parsed.header === null &&
 		parsed.body === null &&
 		parsed.footer === null
 	) {
 		// Commit is empty, skip
-		return {
-			valid: true,
-			errors: [],
-			warnings: [],
-			input: message
-		};
+		return LintOutcome.empty({message});
 	}
 
 	const allRules: Map<string, Rule<unknown> | Rule<never>> = new Map(
@@ -79,7 +68,7 @@ export default async function lint(
 		);
 	}
 
-	const invalid = toPairs(rulesConfig)
+	const invalid = Object.entries(rulesConfig)
 		.map(([name, config]) => {
 			if (!Array.isArray(config)) {
 				return new Error(
@@ -146,7 +135,7 @@ export default async function lint(
 	}
 
 	// Validate against all rules
-	const results = toPairs(rulesConfig)
+	const results = Object.entries(rulesConfig)
 		.filter(([, [level]]) => level > 0)
 		.map(entry => {
 			const [name, config] = entry;
@@ -175,17 +164,8 @@ export default async function lint(
 		})
 		.filter((result): result is LintRuleOutcome => result !== null);
 
-	const errors = results.filter(result => result.level === 2 && !result.valid);
-	const warnings = results.filter(
-		result => result.level === 1 && !result.valid
-	);
-
-	const valid = errors.length === 0;
-
-	return {
-		valid,
-		errors,
-		warnings,
-		input: buildCommitMesage(parsed)
-	};
+	return LintOutcome.fromResults({
+		results,
+		parsed
+	});
 }