feat: support Conventional Commits via --type flag (#177)

Co-authored-by: Hiroki Osame <hiroki.osame@gmail.com>

src/cli.ts

@@ -35,6 +35,11 @@ cli(
 				alias: 'a',
 				default: false,
 			},
+			type: {
+				type: String,
+				description: 'Type of commit message to generate',
+				alias: 't',
+			},
 		},
 
 		commands: [
@@ -56,6 +61,7 @@ cli(
 				argv.flags.generate,
 				argv.flags.exclude,
 				argv.flags.all,
+				argv.flags.type,
 				rawArgv,
 			);
 		}

src/commands/aicommits.ts

@@ -18,6 +18,7 @@ export default async (
 	generate: number | undefined,
 	excludeFiles: string[],
 	stageAll: boolean,
+	commitType: string | undefined,
 	rawArgv: string[],
 ) => (async () => {
 	intro(bgCyan(black(' aicommits ')));
@@ -45,6 +46,7 @@ export default async (
 		OPENAI_KEY: env.OPENAI_KEY || env.OPENAI_API_KEY,
 		proxy: env.https_proxy || env.HTTPS_PROXY || env.http_proxy || env.HTTP_PROXY,
 		generate: generate?.toString(),
+		type: commitType?.toString(),
 	});
 
 	const s = spinner();
@@ -58,6 +60,7 @@ export default async (
 			staged.diff,
 			config.generate,
 			config['max-length'],
+			config.type,
 			config.timeout,
 			config.proxy,
 		);

src/commands/prepare-commit-msg-hook.ts

@@ -46,6 +46,7 @@ export default () => (async () => {
 			staged!.diff,
 			config.generate,
 			config['max-length'],
+			config.type,
 			config.timeout,
 			config.proxy,
 		);

src/utils/config.ts

@@ -6,6 +6,10 @@ import type { TiktokenModel } from '@dqbd/tiktoken';
 import { fileExists } from './fs.js';
 import { KnownError } from './error.js';
 
+const commitTypes = ['', 'conventional'] as const;
+
+export type CommitType = typeof commitTypes[number];
+
 const { hasOwnProperty } = Object.prototype;
 export const hasOwn = (object: unknown, key: PropertyKey) => hasOwnProperty.call(object, key);
 
@@ -51,6 +55,15 @@ const configParsers = {
 
 		return parsed;
 	},
+	type(type?: string) {
+		if (!type) {
+			return '';
+		}
+
+		parseAssert('type', commitTypes.includes(type as CommitType), 'Invalid commit type');
+
+		return type as CommitType;
+	},
 	proxy(url?: string) {
 		if (!url || url.length === 0) {
 			return undefined;
@@ -99,7 +112,7 @@ type RawConfig = {
 	[key in ConfigKeys]?: string;
 };
 
-type ValidConfig = {
+export type ValidConfig = {
 	[Key in ConfigKeys]: ReturnType<typeof configParsers[Key]>;
 };
 

src/utils/openai.ts

@@ -1,6 +1,6 @@
 import https from 'https';
 import type { ClientRequest, IncomingMessage } from 'http';
-import type { CreateChatCompletionRequest, CreateChatCompletionResponse } from 'openai';
+import type { ChatCompletionRequestMessage, CreateChatCompletionRequest, CreateChatCompletionResponse } from 'openai';
 import {
 	TiktokenModel,
 	// eslint-disable-next-line camelcase
@@ -8,6 +8,7 @@ import {
 } from '@dqbd/tiktoken';
 import createHttpsProxyAgent from 'https-proxy-agent';
 import { KnownError } from './error.js';
+import type { CommitType } from './config.js';
 
 const httpsPost = async (
 	hostname: string,
@@ -104,16 +105,51 @@ const sanitizeMessage = (message: string) => message.trim().replace(/[\n\r]/g, '
 
 const deduplicateMessages = (array: string[]) => Array.from(new Set(array));
 
-const getPrompt = (
+const getBasePrompt = (
 	locale: string,
-	diff: string,
 	maxLength: number,
 ) => `${[
 	'Generate a concise git commit message written in present tense for the following code diff with the given specifications below:',
 	`Message language: ${locale}`,
 	`Commit message must be a maximum of ${maxLength} characters.`,
 	'Exclude anything unnecessary such as translation. Your entire response will be passed directly into git commit.',
-].join('\n')}\n\n${diff}`;
+].join('\n')}`;
+
+const getCommitMessageFormatOutputExample = (type: CommitType) => `The output response must be in format:\n${getCommitMessageFormat(type)}`;
+
+const getCommitMessageFormat = (type: CommitType) => {
+	if (type === 'conventional') {
+		return '<type>(<optional scope>): <commit message>';
+	}
+
+	return '<commit message>';
+};
+
+/**
+ * References:
+ * Commitlint:
+ * https://github.com/conventional-changelog/commitlint/blob/18fbed7ea86ac0ec9d5449b4979b762ec4305a92/%40commitlint/config-conventional/index.js#L40-L100
+ *
+ * Conventional Changelog:
+ * https://github.com/conventional-changelog/conventional-changelog/blob/d0e5d5926c8addba74bc962553dd8bcfba90e228/packages/conventional-changelog-conventionalcommits/writer-opts.js#L182-L193
+ */
+const getExtraContextForConventionalCommits = () => (
+	`Choose a type from the type-to-description JSON below that best describes the git diff:\n${
+		JSON.stringify({
+			docs: 'Documentation only changes',
+			style: 'Changes that do not affect the meaning of the code (white-space, formatting, missing semi-colons, etc)',
+			refactor: 'A code change that neither fixes a bug nor adds a feature',
+			perf: 'A code change that improves performance',
+			test: 'Adding missing tests or correcting existing tests',
+			build: 'Changes that affect the build system or external dependencies',
+			ci: 'Changes to our CI configuration files and scripts',
+			chore: "Other changes that don't modify src or test files",
+			revert: 'Reverts a previous commit',
+			feat: 'A new feature',
+			fix: 'A bug fix',
+		}, null, 2)
+	}`
+);
 
 const generateStringFromLength = (length: number) => {
 	let result = '';
@@ -139,10 +175,28 @@ export const generateCommitMessage = async (
 	diff: string,
 	completions: number,
 	maxLength: number,
+	type: CommitType,
 	timeout: number,
 	proxy?: string,
 ) => {
-	const prompt = getPrompt(locale, diff, maxLength);
+	const prompt = getBasePrompt(locale, maxLength);
+
+	const conventionalCommitsExtraContext = type === 'conventional'
+		? getExtraContextForConventionalCommits()
+		: '';
+
+	const commitMessageFormatOutputExample = getCommitMessageFormatOutputExample(type);
+
+	const messages: ChatCompletionRequestMessage[] = [
+		{
+			role: 'system',
+			content: `${prompt}\n${conventionalCommitsExtraContext}\n${commitMessageFormatOutputExample}`,
+		},
+		{
+			role: 'user',
+			content: diff,
+		},
+	];
 
 	// Padded by 5 for more room for the completion.
 	const stringFromLength = generateStringFromLength(maxLength + 5);
@@ -155,10 +209,7 @@ export const generateCommitMessage = async (
 			apiKey,
 			{
 				model,
-				messages: [{
-					role: 'user',
-					content: prompt,
-				}],
+				messages,
 				temperature: 0.7,
 				top_p: 1,
 				frequency_penalty: 0,