From 0ecc038d41b83d1118b3c9064157c305071093d1 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Steffen=20Viken=20Valv=C3=A5g?= <stvikenv@microsoft.com>
Date: Mon, 21 Jan 2019 17:55:09 +0100
Subject: [PATCH] - Add default type parameters {} to all exported types for
 improved backwards compatibility. - Infer option types for positional
 options. - Add tests for command modules and command builders.

---
 types/yargs/index.d.ts     | 13 ++++---
 types/yargs/yargs-tests.ts | 78 ++++++++++++++++++++++++++++++++++++++
 2 files changed, 85 insertions(+), 6 deletions(-)

diff --git a/types/yargs/index.d.ts b/types/yargs/index.d.ts
index 005c05e436..d5a67c56b9 100644
--- a/types/yargs/index.d.ts
+++ b/types/yargs/index.d.ts
@@ -176,7 +176,8 @@ declare namespace yargs {
          * 'positional' should be called in a command's builder function, and is not
          * available on the top-level yargs instance. If so, it will throw an error.
          */
-        positional(key: string, opt: PositionalOptions): Argv<T>;
+        positional<K extends keyof T, O extends PositionalOptions>(key: K, opt: O): Argv<Omit<T, K> & { [key in K]: InferredOptionType<O> }>;
+        positional<K extends string, O extends PositionalOptions>(key: K, opt: O): Argv<T & { [key in K]: InferredOptionType<O> }>;
 
         recommendCommands(): Argv<T>;
 
@@ -252,7 +253,7 @@ declare namespace yargs {
         wrap(columns: number | null): Argv<T>;
     }
 
-    type Arguments<T> = T & {
+    type Arguments<T = {}> = T & {
         /** Non-option arguments */
         _: string[];
         /** The script name or node command */
@@ -376,7 +377,7 @@ declare namespace yargs {
 
     type InferredOptionTypes<O extends { [key: string]: Options }> = { [key in keyof O]: InferredOptionType<O[key]> };
 
-    interface CommandModule<T, U> {
+    interface CommandModule<T = {}, U = {}> {
         aliases?: ReadonlyArray<string> | string;
         builder?: CommandBuilder<T, U>;
         command?: ReadonlyArray<string> | string;
@@ -384,11 +385,11 @@ declare namespace yargs {
         handler: (args: Arguments<U>) => void;
     }
 
-    type ParseCallback<T> = (err: Error | undefined, argv: Arguments<T>, output: string) => void;
-    type CommandBuilder<T, U> = { [key: string]: Options } | ((args: Argv<T>) => Argv<U>);
+    type ParseCallback<T = {}> = (err: Error | undefined, argv: Arguments<T>, output: string) => void;
+    type CommandBuilder<T = {}, U = {}> = { [key: string]: Options } | ((args: Argv<T>) => Argv<U>);
     type SyncCompletionFunction = (current: string, argv: any) => string[];
     type AsyncCompletionFunction = (current: string, argv: any, done: (completion: ReadonlyArray<string>) => void) => void;
-    type MiddlewareFunction<T> = (args: Arguments<T>) => void;
+    type MiddlewareFunction<T = {}> = (args: Arguments<T>) => void;
     type Choices = ReadonlyArray<string | true | undefined>;
     type PositionalOptionsType = "boolean" | "number" | "string";
 }
diff --git a/types/yargs/yargs-tests.ts b/types/yargs/yargs-tests.ts
index 298ee9c9ef..605a986eaf 100644
--- a/types/yargs/yargs-tests.ts
+++ b/types/yargs/yargs-tests.ts
@@ -307,6 +307,84 @@ function Argv$command() {
         .argv;
 }
 
+function Argv$commandModule() {
+    class CommandOne implements yargs.CommandModule {
+        handler(args: yargs.Arguments): void {
+            console.log("one");
+        }
+    }
+
+    const CommandTwo: yargs.CommandModule<{ a: string }, { b: number }> = {
+        builder: yargs => {
+            // $ExpectType: string
+            yargs.argv.a;
+            return yargs.number("b").default("b", parseInt(yargs.argv.a, 10));
+        },
+
+        handler: argv => {
+            // $ExpectType: number
+            argv.b;
+        }
+    };
+
+    class Configure implements yargs.CommandModule<{ verbose: boolean }, { verbose: boolean, key: string, value: boolean }> {
+        command = 'configure <key> [value]';
+        aliases = ['config', 'cfg'];
+        describe = 'Set a config variable';
+
+        builder(yargs: yargs.Argv<{ verbose: boolean }>) {
+            return yargs.positional('key', { default: '' }).positional('value', { default: true });
+        }
+
+        handler(argv: yargs.Arguments<{ verbose: boolean, key: string, value: string | boolean }>) {
+            if (argv.verbose) {
+                console.log(`setting ${argv.key} to ${argv.value}`);
+            }
+        }
+    }
+
+    const Configure2: yargs.CommandModule<{ verbose: boolean }, { verbose: boolean, key: string, value: boolean }> = {
+        command: 'configure <key> [value]',
+        aliases: ['config', 'cfg'],
+        describe: 'Set a config variable',
+
+        builder: yargs => {
+            return yargs.positional('key', { default: '' }).positional('value', { default: true });
+        },
+
+        handler: argv => {
+            if (argv.verbose) {
+                console.log(`setting ${argv.key} to ${argv.value}`);
+            }
+        }
+    };
+
+    const command = 'import-file <file>';
+    const describe = 'run the importer on a single file';
+    const builder = (yargs: yargs.Argv) => {
+        return yargs
+            .positional('file', {
+                describe: 'path to file to import'
+            })
+            .options({
+                cleanDestination: {
+                    boolean: true,
+                    describe: 'Clean the destination folder from previously generated files before proceeding.'
+                }
+            });
+    };
+
+    const commandArgs = builder(yargs).argv;
+
+    // $ExpectType: { [x: string]: unknown; file: unknown; cleanDestination: boolean | undefined; _: string[]; $0: string; }
+    commandArgs;
+
+    // Backwards compatibility with older types
+    const builder2: yargs.CommandBuilder = builder;
+    const commandArgs2: yargs.Arguments = builder(yargs).argv;
+    const commandArgs3: yargs.Arguments = builder2(yargs).argv;
+}
+
 function Argv$completion_sync() {
     const argv = yargs
         .completion('completion', (current, argv) => {