style: update tsconfig and Middy type usage

.gitignore

@@ -204,4 +204,7 @@ $RECYCLE.BIN/
 *.js
 !.eslintrc.js
 *.js.map
-samconfig.toml
+samconfig.toml
+*.d.ts
+.vscode/
+

bin/summarise.ts

@@ -1,10 +1,10 @@
 #!/usr/bin/env ./node_modules/.bin/ts-node
 
-import { readFileSync } from 'fs'
+import { readFileSync } from 'node:fs'
 import { createSummary } from '../lib/summarisation'
 
 import yargs from 'yargs'
-import { Transcript } from '../lib/types'
+import type { Transcript } from '../lib/types'
 
 interface Argv {
   transcriptFilePath: string
@@ -15,20 +15,19 @@ const argv: Argv = yargs
   .usage('Usage: $0 <transcriptFilePath>')
   .command('$0 <transcriptFilePath>', 'path to the transcript JSON file')
   .options('bedrock-region', {
-    default: 'us-east-1'
+    default: 'us-east-1',
   })
   .alias('h', 'help')
   .help('help')
-  .demandCommand(1, 'You need to provide a filename argument.')
-  .argv as unknown as Argv
+  .demandCommand(1, 'You need to provide a filename argument.').argv as unknown as Argv
 
 const filename: string = argv.transcriptFilePath
 const transcriptContents = readFileSync(filename, 'utf8')
 const transcript = JSON.parse(transcriptContents)
 
 summarise(transcript)
 
-async function summarise (transcript: Transcript): Promise<void> {
+async function summarise(transcript: Transcript): Promise<void> {
   const summary = await createSummary(transcript, { bedrockRegion: argv.bedrockRegion })
   console.log(JSON.stringify(summary, null, 4))
 }

biome.json

@@ -0,0 +1,33 @@
+{
+  "$schema": "https://biomejs.dev/schemas/1.9.4/schema.json",
+  "vcs": {
+    "enabled": true,
+    "clientKind": "git",
+    "useIgnoreFile": true
+  },
+  "files": {
+    "ignoreUnknown": false,
+    "ignore": []
+  },
+  "formatter": {
+    "enabled": true,
+    "indentStyle": "space",
+    "indentWidth": 2,
+    "lineWidth": 120
+  },
+  "organizeImports": {
+    "enabled": true
+  },
+  "linter": {
+    "enabled": true,
+    "rules": {
+      "recommended": true
+    }
+  },
+  "javascript": {
+    "formatter": {
+      "quoteStyle": "single",
+      "semicolons": "asNeeded"
+    }
+  }
+}

events/sample-pr-event.json

@@ -35,4 +35,4 @@
     ]
   },
   "transcriptKey": "processed-transcripts/998.json"
-}
+}

functions/pull-request/app.ts

@@ -1,14 +1,14 @@
-import path from 'node:path'
-import { tmpdir } from 'node:os'
 import { mkdir, mkdtemp, rm, writeFile } from 'node:fs/promises'
-import { simpleGit } from 'simple-git'
-import { SSMClient, GetParameterCommand } from '@aws-sdk/client-ssm'
+import { tmpdir } from 'node:os'
+import path from 'node:path'
 import { S3Client } from '@aws-sdk/client-s3'
+import { GetParameterCommand, SSMClient } from '@aws-sdk/client-ssm'
 import { Octokit } from 'octokit'
+import { simpleGit } from 'simple-git'
 
 import envs from '../../lib/envs'
-import type { Summary } from '../../lib/types'
 import { logger, middify } from '../../lib/lambda-common'
+import type { Summary } from '../../lib/types'
 import { getS3JSON } from '../../lib/utils'
 import { createPullRequestDescription } from './pr-description'
 
@@ -21,10 +21,12 @@ const ssmClient = new SSMClient({})
 const s3Client = new S3Client({})
 
 // A personal access token is used to clone and push from/to GitHub
-const gitHubUserCredentialsPromise = ssmClient.send(new GetParameterCommand({
-  Name: GIT_HUB_CREDENTIALS_SSM_PARAMETER,
-  WithDecryption: true
-}))
+const gitHubUserCredentialsPromise = ssmClient.send(
+  new GetParameterCommand({
+    Name: GIT_HUB_CREDENTIALS_SSM_PARAMETER,
+    WithDecryption: true,
+  }),
+)
 
 interface PullRequestEvent {
   transcriptKey: string
@@ -59,7 +61,9 @@ export const handleEvent = middify(async (event: PullRequestEvent) => {
     }
     const [username, password] = gitHubUserCredentials.split(':')
     if (username === undefined || password === undefined || username === '' || password === '') {
-      throw new Error(`${GIT_HUB_CREDENTIALS_SSM_PARAMETER} SSM Parameter should be in the format <Username>:<GitHubPersonalAccessToken>`)
+      throw new Error(
+        `${GIT_HUB_CREDENTIALS_SSM_PARAMETER} SSM Parameter should be in the format <Username>:<GitHubPersonalAccessToken>`,
+      )
     }
 
     const gitUrl = new URL(GIT_REPO_URL)
@@ -97,9 +101,14 @@ export const handleEvent = middify(async (event: PullRequestEvent) => {
     const base = TARGET_BRANCH === undefined ? 'main' : TARGET_BRANCH
     const repoPath = gitUrl.pathname
     const [, owner] = repoPath.split('/')
-    const response = await octokit.request(
-      `POST /repos/${owner}/${repoName}/pulls`, { owner, title, body, head, base, repo: repoName }
-    )
+    const response = await octokit.request(`POST /repos/${owner}/${repoName}/pulls`, {
+      owner,
+      title,
+      body,
+      head,
+      base,
+      repo: repoName,
+    })
     const prUrl = response.data.html_url
     console.log('Created PR', { prUrl })
     return { prUrl }

functions/pull-request/pr-description.ts

@@ -1,14 +1,14 @@
-import { Summary } from '../../lib/types'
+import type { Summary } from '../../lib/types'
 
 /**
  * Convert decimal seconds to mm:ss format
  *
  * @param seconds seconds
  * @returns a string like '00:00' or '123:59'
  */
-export function secondsToYtTime (seconds: number): string {
+export function secondsToYtTime(seconds: number): string {
   const hours = String(Math.floor(seconds / 3600))
-  const minutes = String(Math.floor(seconds % 3600 / 60))
+  const minutes = String(Math.floor((seconds % 3600) / 60))
   const roundedSeconds = String(Math.floor(seconds % 60))
   let res = ''
   if (hours !== '0') {
@@ -21,8 +21,8 @@ export function secondsToYtTime (seconds: number): string {
 /**
  * Create a PR markdown description from the generated summary of the episode and chapters
  */
-export function createPullRequestDescription (summary: Summary): string {
-  const ytChapters = summary.chapters.map(c => `${secondsToYtTime(c.startTimestamp)} ${c.summary}`).join('\n')
+export function createPullRequestDescription(summary: Summary): string {
+  const ytChapters = summary.chapters.map((c) => `${secondsToYtTime(c.startTimestamp)} ${c.summary}`).join('\n')
   return `
 # Transcript
 

functions/summary/app.ts

@@ -1,12 +1,12 @@
 import path from 'node:path'
-import { S3Client } from '@aws-sdk/client-s3'
 import { MetricUnits } from '@aws-lambda-powertools/metrics'
+import { S3Client } from '@aws-sdk/client-s3'
 
 import envs from '../../lib/envs'
 import { logger, metrics, middify, tracer } from '../../lib/lambda-common'
-import { getS3JSON } from '../../lib/utils'
 import { createSummary } from '../../lib/summarisation'
-import { Summary, Transcript } from '../../lib/types'
+import type { Summary, Transcript } from '../../lib/types'
+import { getS3JSON } from '../../lib/utils'
 
 const { BUCKET_NAME } = envs
 
@@ -36,6 +36,6 @@ export const handleEvent = middify(async (event: SummarisationEvent): Promise<Su
   metrics.addMetric('ChapterCount', MetricUnits.Count, summary.chapters.length)
 
   return {
-    summary
+    summary,
   }
 })

lib/envs.ts

@@ -5,14 +5,17 @@ type Environment = Record<string, string>
  * `env.BUCKET_NAME` will throw an Error if BUCKET_NAME is not defined in the environment.
  * This eliminates the need to check the existence of each environment variable where it is used.
  */
-const envProxy: Environment = new Proxy({}, {
-  get (_target: Record<string, string>, name: string): string {
-    const value = process.env[name]
-    if (value === undefined) {
-      throw new Error(`Environment variable ${name} is not set`)
-    }
-    return value
-  }
-})
+const envProxy: Environment = new Proxy(
+  {},
+  {
+    get(_target: Record<string, string>, name: string): string {
+      const value = process.env[name]
+      if (value === undefined) {
+        throw new Error(`Environment variable ${name} is not set`)
+      }
+      return value
+    },
+  },
+)
 
 export default envProxy

lib/lambda-common.ts

@@ -2,22 +2,28 @@ import { Logger, injectLambdaContext } from '@aws-lambda-powertools/logger'
 import { Metrics, logMetrics } from '@aws-lambda-powertools/metrics'
 import { Tracer, captureLambdaHandler } from '@aws-lambda-powertools/tracer'
 import middy from '@middy/core'
-import { Handler } from 'aws-lambda'
+import type { Context } from 'aws-lambda'
 
 // Exported powertools instances for use anywhere within a Lambda function implementation
 export const logger = new Logger()
 export const tracer = new Tracer()
 export const metrics = new Metrics()
 
+export type LambdaPromiseHandler<TEvent, TResult> = (event: TEvent, context: Context) => Promise<TResult>
+
 /**
  * Create a wrapped Lambda Function handler with injected powertools logger, tracer and metrics
  *
  * @param handler The undecorated Lambda Function handler
  * @returns A 'middified' handler
  */
-export const middify = (handler: Handler): Handler => {
-  return middy(handler)
+
+export const middify = <TEvent, TResult>(
+  handler: LambdaPromiseHandler<TEvent, TResult>,
+): LambdaPromiseHandler<TEvent, TResult> => {
+  return middy<TEvent, TResult>()
     .use(injectLambdaContext(logger, { logEvent: true }))
     .use(logMetrics(metrics))
     .use(captureLambdaHandler(tracer))
+    .handler(handler)
 }

lib/prompt-template.ts

@@ -1,6 +1,6 @@
-import { Transcript } from './types'
+import type { Transcript } from './types'
 
-export function createPrompt (transcript: Transcript): string {
+export function createPrompt(transcript: Transcript): string {
   return `Human: Please provide a friendly, positive episode summary (first-person plural and at least 120 words),
 followed by at least 10 chapter summaries for the following podcast transcript JSON.
 The transcript segments have start and end time in floating point seconds.

lib/summarisation.ts

@@ -1,7 +1,7 @@
 import { BedrockRuntimeClient, InvokeModelCommand } from '@aws-sdk/client-bedrock-runtime'
-import { Summary, Transcript } from './types'
 import envs from './envs'
 import { createPrompt } from './prompt-template'
+import type { Summary, Transcript } from './types'
 
 const MODEL_ID = 'anthropic.claude-v2'
 
@@ -10,9 +10,14 @@ const MODEL_ID = 'anthropic.claude-v2'
  *
  * @param transcript The episode transcript
  */
-export async function createSummary (transcript: Transcript, options: { bedrockRegion?: string } = {}): Promise<Summary> {
+export async function createSummary(
+  transcript: Transcript,
+  options: { bedrockRegion?: string } = {},
+): Promise<Summary> {
   const { bedrockRegion } = options
-  const brClient = new BedrockRuntimeClient({ region: bedrockRegion === undefined ? envs.BEDROCK_REGION : bedrockRegion })
+  const brClient = new BedrockRuntimeClient({
+    region: bedrockRegion === undefined ? envs.BEDROCK_REGION : bedrockRegion,
+  })
 
   const prompt = createPrompt(transcript)
   const modelInput = JSON.stringify({
@@ -21,14 +26,14 @@ export async function createSummary (transcript: Transcript, options: { bedrockR
     temperature: 0.5,
     top_k: 250,
     top_p: 1,
-    stop_sequences: []
+    stop_sequences: [],
   })
 
   const invokeModelCommand = new InvokeModelCommand({
     body: modelInput,
     modelId: MODEL_ID,
     accept: 'application/json',
-    contentType: 'application/json'
+    contentType: 'application/json',
   })
 
   const modelResponse = await brClient.send(invokeModelCommand)

lib/utils.ts

@@ -1,4 +1,4 @@
-import { Readable } from 'node:stream'
+import type { Readable } from 'node:stream'
 import { GetObjectCommand, type S3Client } from '@aws-sdk/client-s3'
 import { logger } from './lambda-common'
 
@@ -10,16 +10,18 @@ import { logger } from './lambda-common'
  * @param key The S3 object key
  * @returns The retrieved JSON as an object
  */
-export async function getS3JSON<T = any> (s3Client: S3Client, bucket: string, key: string): Promise<T> {
+export async function getS3JSON<T = unknown>(s3Client: S3Client, bucket: string, key: string): Promise<T> {
   logger.info('Getting object', { bucket, key })
-  const response = await s3Client.send(new GetObjectCommand({
-    Bucket: bucket,
-    Key: key
-  }))
+  const response = await s3Client.send(
+    new GetObjectCommand({
+      Bucket: bucket,
+      Key: key,
+    }),
+  )
 
-  const chunks = []
-  for await (const chunk of response.Body as any as Readable) {
-    chunks.push(chunk as never)
+  const chunks: Uint8Array[] = []
+  for await (const chunk of response.Body as unknown as Readable) {
+    chunks.push(chunk as Uint8Array)
   }
 
   return JSON.parse(Buffer.concat(chunks).toString('utf-8'))