refactor: organize prompt generation to its own file

src/utils/openai.ts

@@ -1,6 +1,6 @@
 import https from 'https';
 import type { ClientRequest, IncomingMessage } from 'http';
-import type { ChatCompletionRequestMessage, CreateChatCompletionRequest, CreateChatCompletionResponse } from 'openai';
+import type { CreateChatCompletionRequest, CreateChatCompletionResponse } from 'openai';
 import {
 	type TiktokenModel,
 	// encoding_for_model,
@@ -8,6 +8,7 @@ import {
 import createHttpsProxyAgent from 'https-proxy-agent';
 import { KnownError } from './error.js';
 import type { CommitType } from './config.js';
+import { generatePrompt } from './prompt.js';
 
 const httpsPost = async (
 	hostname: string,
@@ -104,52 +105,6 @@ const sanitizeMessage = (message: string) => message.trim().replace(/[\n\r]/g, '
 
 const deduplicateMessages = (array: string[]) => Array.from(new Set(array));
 
-const getBasePrompt = (
-	locale: 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 ${maxLength} characters.`,
-	'Exclude anything unnecessary such as translation. Your entire response will be passed directly into git commit.',
-].join('\n')}`;
-
-const getCommitMessageFormatOutputExample = (type: CommitType) => `The output response must be in format:\n${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${
-		JSON.stringify({
-			docs: 'Documentation only changes',
-			style: 'Changes that do not affect the meaning of the code (white-space, formatting, missing semi-colons, etc)',
-			refactor: 'A code change that neither fixes a bug nor adds a feature',
-			perf: 'A code change that improves performance',
-			test: 'Adding missing tests or correcting existing tests',
-			build: 'Changes that affect the build system or external dependencies',
-			ci: 'Changes to our CI configuration files and scripts',
-			chore: "Other changes that don't modify src or test files",
-			revert: 'Reverts a previous commit',
-			feat: 'A new feature',
-			fix: 'A bug fix',
-		}, null, 2)
-	}`
-);
-
 // const generateStringFromLength = (length: number) => {
 // 	let result = '';
 // 	const highestTokenChar = 'z';
@@ -178,31 +133,21 @@ export const generateCommitMessage = async (
 	timeout: number,
 	proxy?: string,
 ) => {
-	const prompt = getBasePrompt(locale, maxLength);
-
-	const conventionalCommitsExtraContext = type === 'conventional'
-		? getExtraContextForConventionalCommits()
-		: '';
-
-	const commitMessageFormatOutputExample = getCommitMessageFormatOutputExample(type);
-
-	const messages: ChatCompletionRequestMessage[] = [
-		{
-			role: 'system',
-			content: `${prompt}\n${conventionalCommitsExtraContext}\n${commitMessageFormatOutputExample}`,
-		},
-		{
-			role: 'user',
-			content: diff,
-		},
-	];
-
 	try {
 		const completion = await createChatCompletion(
 			apiKey,
 			{
 				model,
-				messages,
+				messages: [
+					{
+						role: 'system',
+						content: generatePrompt(locale, maxLength, type),
+					},
+					{
+						role: 'user',
+						content: diff,
+					},
+				],
 				temperature: 0.7,
 				top_p: 1,
 				frequency_penalty: 0,

src/utils/prompt.ts

@@ -0,0 +1,48 @@
+import type { CommitType } from './config.js';
+
+const commitTypeFormats: Record<CommitType, string> = {
+	'': '<commit message>',
+	conventional: '<type>(<optional scope>): <commit message>',
+};
+const specifyCommitFormat = (type: CommitType) => `The output response must be in format:\n${commitTypeFormats[type]}`;
+
+const commitTypes: Record<CommitType, string> = {
+	'': '',
+
+	/**
+	 * References:
+	 * Commitlint:
+	 * https://github.com/conventional-changelog/commitlint/blob/18fbed7ea86ac0ec9d5449b4979b762ec4305a92/%40commitlint/config-conventional/index.js#L40-L100
+	 *
+	 * Conventional Changelog:
+	 * https://github.com/conventional-changelog/conventional-changelog/blob/d0e5d5926c8addba74bc962553dd8bcfba90e228/packages/conventional-changelog-conventionalcommits/writer-opts.js#L182-L193
+	 */
+	conventional: `Choose a type from the type-to-description JSON below that best describes the git diff:\n${
+		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)
+	}`,
+};
+
+export const generatePrompt = (
+	locale: string,
+	maxLength: number,
+	type: CommitType,
+) => [
+	'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.',
+	commitTypes[type],
+	specifyCommitFormat(type),
+].filter(Boolean).join('\n');