Add --debug (-d) option to CLI interface

marp-cli.js

@@ -1,7 +1,14 @@
 #!/usr/bin/env node
 
 'use strict'
+{
+  const prepare = require('./lib/prepare.js')
+  const cli = prepare.cliPrepare()
 
-require('./lib/marp-cli.js')
-  .cliInterface(process.argv.slice(2))
-  .then((exitCode) => process.on('exit', () => process.exit(exitCode)))
+  if (cli.debug)
+    process.env.DEBUG = `${process.env.DEBUG ? `${process.env.DEBUG},` : ''}${cli.debug}`
+
+  require('./lib/marp-cli.js')
+    .cliInterface(cli.args)
+    .then((exitCode) => process.on('exit', () => process.exit(exitCode)))
+}

rollup.config.mjs

@@ -91,7 +91,11 @@ export default [
   },
   {
     ...cli,
-    input: ['src/marp-cli.ts', 'src/index.ts'],
+    input: [
+      'src/index.ts', // Node.js entrypoint
+      'src/marp-cli.ts', // CLI entrypoint
+      'src/prepare.ts', // CLI preparation
+    ],
     output: { compact, dir: 'lib', exports: 'named', format: 'cjs' },
   },
 ]

src/marp-cli.ts

@@ -22,13 +22,17 @@ enum OptionGroup {
   Marp = 'Marp / Marpit Options:',
 }
 
-export interface MarpCLIInternalOptions {
+export interface MarpCLIOptions {
   baseUrl?: string
   stdin: boolean
   throwErrorAlways: boolean
 }
 
-export type MarpCLIAPIOptions = Pick<MarpCLIInternalOptions, 'baseUrl'>
+export type MarpCLIAPIOptions = Pick<MarpCLIOptions, 'baseUrl'>
+
+export interface MarpCLICLIOptions {
+  debug?: string | boolean
+}
 
 export interface ObservationHelper {
   stop: () => void
@@ -44,7 +48,7 @@ Usage:
 
 export const marpCli = async (
   argv: string[],
-  { baseUrl, stdin: defaultStdin, throwErrorAlways }: MarpCLIInternalOptions
+  { baseUrl, stdin: defaultStdin, throwErrorAlways }: MarpCLIOptions
 ): Promise<number> => {
   let browserManager: BrowserManager | undefined
   let server: Server | undefined
@@ -69,6 +73,14 @@ export const marpCli = async (
           group: OptionGroup.Basic,
           type: 'boolean',
         },
+        debug: {
+          // NOTE: This option will not be parsed by yargs because it has been pre-parsed by prepare.ts
+          alias: 'd',
+          describe: 'Show debug logs (bool or filter pattern)',
+          defaultDescription: 'false',
+          group: OptionGroup.Basic,
+          type: 'string',
+        },
         output: {
           alias: 'o',
           describe: 'Output file path (or directory when input-dir is passed)',
@@ -181,7 +193,7 @@ export const marpCli = async (
         },
         template: {
           describe: 'Choose template',
-          defaultDescription: 'bespoke',
+          defaultDescription: '"bespoke"',
           group: OptionGroup.Template,
           choices: Object.keys(templates),
           type: 'string',
@@ -469,7 +481,13 @@ export const waitForObservation = () =>
 export const apiInterface = (argv: string[], opts: MarpCLIAPIOptions = {}) =>
   marpCli(argv, { ...opts, stdin: false, throwErrorAlways: true })
 
-export const cliInterface = (argv: string[] = []) =>
-  marpCli(argv, { stdin: true, throwErrorAlways: false })
+export const cliInterface = (argv: string[], opts: MarpCLICLIOptions = {}) => {
+  if (process.env.DEBUG) {
+    cli.info(
+      `Debug logging is enabled. (Filter pattern: ${chalk.yellow(process.env.DEBUG)})`
+    )
+  }
+  return marpCli(argv, { stdin: true, throwErrorAlways: false })
+}
 
 export default cliInterface

src/prepare.ts

@@ -0,0 +1,47 @@
+export const defaultDebug = 'marp-cli*'
+
+const debugOptionMatcher = /^(?:-d|--debug)(?:$|=)/
+
+const enableValues = ['true', '1']
+const falseValues = ['false', '0']
+const starValues = ['all', 'full']
+
+const parseDebugValue = (value: string) => {
+  const trimmedValue = value.trim()
+  const normalizedValue = trimmedValue.toLowerCase()
+
+  if (starValues.includes(normalizedValue)) return '*'
+  if (enableValues.includes(normalizedValue)) return defaultDebug
+  if (falseValues.includes(normalizedValue)) return false
+
+  return trimmedValue || defaultDebug
+}
+
+export const cliPrepare = (args = process.argv.slice(2)) => {
+  // Parse debug option
+  let debug: string | false = false
+
+  const normalizedArgs = [...args]
+  const dbgIdx = normalizedArgs.findIndex((arg) => debugOptionMatcher.test(arg))
+
+  if (dbgIdx >= 0) {
+    const dbgOption = normalizedArgs[dbgIdx]
+
+    if (dbgOption.startsWith('-d=') || dbgOption.startsWith('--debug=')) {
+      debug = parseDebugValue(dbgOption.slice(dbgOption.indexOf('=') + 1))
+      normalizedArgs.splice(dbgIdx, 1)
+    } else {
+      const nextArg = normalizedArgs[dbgIdx + 1]
+
+      if (!nextArg || nextArg.startsWith('-')) {
+        debug = defaultDebug
+        normalizedArgs.splice(dbgIdx, 1)
+      } else {
+        debug = parseDebugValue(nextArg)
+        normalizedArgs.splice(dbgIdx, 2)
+      }
+    }
+  }
+
+  return { args: normalizedArgs, debug }
+}

test/index.ts

@@ -17,7 +17,7 @@ describe('Marp CLI API interface', () => {
       expect(ret).toBe(0)
       expect(marpCliSpy).toHaveBeenCalled()
 
-      const opts: marpCli.MarpCLIInternalOptions = marpCliSpy.mock.calls[0][1]
+      const opts: marpCli.MarpCLIOptions = marpCliSpy.mock.calls[0][1]
 
       expect(opts.baseUrl).toBe('https://example.com/')
       expect(opts.stdin).toBe(false)