feat: add option to pass yargs parserConfiguration

README.md

@@ -375,11 +375,14 @@ Creates a new program. Options (object, optional) can contain these keys:
   displays program usage information.
 - `version` (boolean, default: true) adds `version` and `--version` to the
   program which displays program version from package.json.
-- `historyFile` (string | null, defaults: {homedir}/.bandersnatch_history) is a
+- `historyFile` (string | null, default: {homedir}/.bandersnatch_history) is a
   path to the app history file. Set to NULL to disable.
-- `exit` (boolean | () => void, default: () => process.exit()) Specifies whether to add a default behaviour for an `exit`
-  command. `false` disables the default implementation, a custom function will be installed
-  as the actual handler.
+- `exit` (boolean | () => void, default: () => process.exit()) Specifies whether
+  to add a default behaviour for an `exit` command. `false` disables the default
+  implementation, a custom function will be installed as the actual handler.
+- `parserConfiguration` (object, optional) can be used to modify the parser
+  configuration. For available options, see
+  - https://github.com/yargs/yargs/blob/main/docs/api.md#parserConfiguration.
 
 #### `program.description(description)`
 

src/autocompleter.ts

@@ -14,7 +14,9 @@ export class Autocompleter {
 
   private yargsCompletions(argv: string[]) {
     return new Promise<string[]>((resolve, reject) => {
-      const yargs = this.program.createYargsInstance()
+      // We need to override 'strip-dashed' to make sure yargs can find the
+      // '--get-yargs-completions' option.
+      const yargs = this.program.createYargsInstance({ 'strip-dashed': false })
 
       // yargs.getCompletion() doesn't work for our use case.
       yargs.parse(

src/program.ts

@@ -2,7 +2,7 @@ import { EventEmitter } from 'events'
 import os from 'os'
 import path from 'path'
 import TypedEventEmitter from 'typed-emitter'
-import { Argv } from 'yargs'
+import { Argv, ParserConfigurationOptions } from 'yargs'
 import createYargs from 'yargs/yargs'
 import { Arguments, Command, command } from './command'
 import { history, History } from './history'
@@ -67,6 +67,14 @@ type ProgramOptions = {
    * Defaults to `() => process.exit()`.
    */
   exit?: boolean | (() => void)
+
+  /**
+   * Pass Yargs parser configuration, for available options, see
+   * https://github.com/yargs/yargs/blob/main/docs/advanced.md#customizing-yargs-parser.
+   *
+   * Defaults to `undefined`.
+   */
+  parserConfiguration?: Partial<ParserConfigurationOptions>
 }
 
 /**
@@ -133,8 +141,10 @@ export class Program extends (EventEmitter as new () => TypedEventEmitter<Events
    *
    * @private
    */
-  public createYargsInstance() {
-    const yargs = createYargs()
+  public createYargsInstance(
+    overrideParserConfiguration?: Partial<ParserConfigurationOptions>
+  ) {
+    let yargs = createYargs()
 
     this.options.description && yargs.usage(this.options.description)
 
@@ -144,6 +154,14 @@ export class Program extends (EventEmitter as new () => TypedEventEmitter<Events
     // Version must be false or undefined
     this.options.version !== false ? yargs.version() : yargs.version(false)
 
+    // Pass yargs parser options if defined
+    if (typeof this.options.parserConfiguration !== 'undefined') {
+      yargs = yargs.parserConfiguration({
+        ...this.options.parserConfiguration,
+        ...overrideParserConfiguration,
+      })
+    }
+
     // Non-configurable options
     yargs.recommendCommands()
     yargs.strict()

tests/program.spec.ts

@@ -50,6 +50,19 @@ test('program executes argv', async () => {
   })
 })
 
+test('program passes parserConfiguration', async () => {
+  await mockArgv(['test', '--test-field', '1'], async () => {
+    const app = program({ parserConfiguration: { 'strip-dashed': true } }).add(
+      command('test')
+        .option('test-field')
+        .action((args) => {
+          return JSON.stringify(args)
+        })
+    )
+    await expect(app.run()).resolves.toBe('{"testField":1}')
+  })
+})
+
 test('program starts repl', async () => {
   const app = program()
   expect(app.repl()).toBeInstanceOf(MockedRepl)