Add type assertions

Author: aweebit

lib/argument.js

@@ -99,8 +99,9 @@ class Argument {
   choices(values) {
     this.argChoices = values.slice();
     this.parseArg = (arg, previous) => {
-      if (!this.argChoices.includes(arg)) {
-        throw new InvalidArgumentError(`Allowed choices are ${this.argChoices.join(', ')}.`);
+      const argChoices = /** @type {string[]} */ (this.argChoices);
+      if (!argChoices.includes(arg)) {
+        throw new InvalidArgumentError(`Allowed choices are ${argChoices.join(', ')}.`);
       }
       if (this.variadic) {
         return this._concatValue(arg, previous);

lib/command.js

@@ -142,7 +142,9 @@ class Command extends EventEmitter {
       desc = null;
     }
     opts = opts || {};
-    const [, name, args] = nameAndArgs.match(/([^ ]+) *(.*)/);
+    const [, name, args] = /** @type {[*, string, string | undefined]} */ (
+      nameAndArgs.match(/([^ ]+) *(.*)/)
+    );
 
     const cmd = this.createCommand(name);
     if (desc) {
@@ -1297,7 +1299,9 @@ Expecting one of '${allowedValues.join("', '")}'`);
 
       let actionResult;
       actionResult = this._chainOrCallHooks(actionResult, 'preAction');
-      actionResult = this._chainOrCall(actionResult, () => this._actionHandler(this.processedArgs));
+      actionResult = this._chainOrCall(actionResult, () => (
+        /** @type {Function} */ (this._actionHandler)(this.processedArgs)
+      ));
       if (this.parent) {
         actionResult = this._chainOrCall(actionResult, () => {
           this.parent.emit(commandEvent, operands, unknown); // legacy
@@ -1446,7 +1450,7 @@ Expecting one of '${allowedValues.join("', '")}'`);
     // parse options
     let activeVariadicOption = null;
     while (args.length) {
-      const arg = args.shift();
+      const arg = /** @type {string} */ (args.shift());
 
       // literal
       if (arg === '--') {

lib/error.js

@@ -9,7 +9,7 @@ class CommanderError extends Error {
    * Constructs the CommanderError class
    * @param {number} exitCode suggested exit code which could be used with process.exit
    * @param {string} code an id string representing the error
-   * @param {string} message human-readable description of the error
+   * @param {string} [message] human-readable description of the error
    * @constructor
    */
   constructor(exitCode, code, message) {

lib/help.js

@@ -30,7 +30,9 @@ class Help {
     const visibleCommands = cmd.commands.filter(cmd => !cmd._hidden);
     if (cmd._hasImplicitHelpCommand()) {
       // Create a command matching the implicit help command.
-      const [, helpName, helpArgs] = cmd._helpCommandnameAndArgs.match(/([^ ]+) *(.*)/);
+      const [, helpName, helpArgs] = /** @type {[*, string, string | undefined]} */ (
+        cmd._helpCommandnameAndArgs.match(/([^ ]+) *(.*)/)
+      );
       const helpCommand = cmd.createCommand(helpName)
         .helpOption(false);
       helpCommand.description(cmd._helpCommandDescription);

lib/option.js

@@ -181,8 +181,9 @@ class Option {
   choices(values) {
     this.argChoices = values.slice();
     this.parseArg = (arg, previous) => {
-      if (!this.argChoices.includes(arg)) {
-        throw new InvalidArgumentError(`Allowed choices are ${this.argChoices.join(', ')}.`);
+      const argChoices = /** @type {string[]} */ (this.argChoices);
+      if (!argChoices.includes(arg)) {
+        throw new InvalidArgumentError(`Allowed choices are ${argChoices.join(', ')}.`);
       }
       if (this.variadic) {
         return this._concatValue(arg, previous);