Add help for positional arguments

packages/argparse/src/argparse.test.ts

@@ -220,6 +220,9 @@ describe('argparse', () => {
         three: arg('boolean'),
       })
       expect(help()).toEqual([
+        '[OPTIONS] ',
+        '',
+        'Options:',
         '    --one string               ',
         '    --two number               ',
         '    --three boolean            ',
@@ -234,12 +237,22 @@ describe('argparse', () => {
           default: 'choice-1',
           alias: 'o',
         }),
-        two: arg('number'),
+        two: arg('number', {
+          positional: true,
+          required: true,
+        }),
+        three: arg('number', {
+          positional: true,
+        }),
       })
       expect(help()).toEqual([
+        '[OPTIONS] TWO [THREE]',
+        '',
+        'Options:',
         '-o, --one string                first argument ' +
           '(required, default: choice-1, choices: choice-1,choice-2)',
-        '    --two number               ',
+        '    --two number                (required)',
+        '    --three number             ',
       ].join('\n'))
     })
 

packages/argparse/src/argparse.ts

@@ -51,9 +51,13 @@ const iterate = <T>(arr: T[]): IIterator<T> => {
   }
 }
 
+function createError(message: string) {
+  return new Error('Error parsing arguments: ' + message)
+}
+
 function assert(cond: boolean, message: string) {
   if (!cond) {
-    throw new Error('Error parsing arguments: ' + message)
+    throw createError(message)
   }
 }
 
@@ -118,7 +122,20 @@ export function padRight(str: string, chars: number) {
 }
 
 export function help(config: IArgsConfig) {
-  return Object.keys(config).map(argument => {
+  const keys = Object.keys(config)
+
+  const positionalHelp = [
+    '[OPTIONS]',
+    keys
+    .filter(k => config[k].positional)
+    .map(k => config[k].required
+      ? `${k.toUpperCase()}`
+      : `[${k.toUpperCase()}]`,
+    )
+    .join(' '),
+  ].join(' ')
+
+  const argsHelp = 'Options:\n' + keys.map(argument => {
     const argConfig = config[argument]
     const {alias, type} = argConfig
     const name = alias
@@ -140,6 +157,10 @@ export function help(config: IArgsConfig) {
     return padRight(name + ' ' + type, 30) + ' ' + description + sample
   })
   .join('\n')
+
+  return [positionalHelp, argsHelp]
+  .filter(h => h.length)
+  .join('\n\n')
 }
 
 export function arg<T extends TArgTypeName>(

packages/scripts/src/commands/build.ts

@@ -1,6 +1,6 @@
 import * as fs from 'fs'
 import * as p from 'path'
-import {argparse} from '@rondo/argparse'
+import {argparse, arg} from '@rondo/argparse'
 import {findNodeModules} from '../modules'
 import {join} from 'path'
 import {run} from '../run'
@@ -8,22 +8,32 @@ import {run} from '../run'
 const tsc = 'ttsc'
 
 export async function build(...argv: string[]) {
-  const {esm, project, watch} = argparse({
-    project: {
-      type: 'string',
+  const {parse, help} = argparse({
+    project: arg('string', {
       alias: 'p',
       default: '.',
-    },
-    esm: {
-      type: 'boolean',
-    },
-    watch: {
-      type: 'boolean',
+      description: 'Project to build',
+      positional: true,
+    }),
+    esm: arg('boolean', {
+      description: 'Build project from tsconfig.esm.json',
+    }),
+    watch: arg('boolean', {
       alias: 'w',
-    },
-  })(argv)
-  const path = esm ? join(project, 'tsconfig.esm.json') : project
-  const watchArgs = watch ? ['--watch', '--preserveWatchOutput'] : []
+      description: 'Watch for changes',
+    }),
+    help: arg('boolean', {
+      alias: 'h',
+      description: 'Print help message',
+    }),
+  })
+  const args = parse(argv)
+  if (args.help) {
+    console.log('Usage: rondo build ' + help())
+    return
+  }
+  const path = args.esm ? join(args.project, 'tsconfig.esm.json') : args.project
+  const watchArgs = args.watch ? ['--watch', '--preserveWatchOutput'] : []
   await run(tsc, ['--build', path, ...watchArgs])
 }
 

packages/scripts/src/index.ts

@@ -17,7 +17,7 @@ async function run(...argv: string[]) {
 if (typeof require !== 'undefined' && require.main === module) {
   run(...process.argv.slice(2))
   .catch(err => {
-    console.log('> ' + err.stack)
+    console.log('> ' + err.message)
     process.exit(1)
   })
 }