Collect variadic

lib/argument.js

@@ -53,12 +53,13 @@ class Argument {
    * @package
    */
 
-  _concatValue(value, previous) {
+  _collectValue(value, previous) {
     if (previous === this.defaultValue || !Array.isArray(previous)) {
       return [value];
     }
 
-    return previous.concat(value);
+    previous.push(value);
+    return previous;
   }
 
   /**
@@ -103,7 +104,7 @@ class Argument {
         );
       }
       if (this.variadic) {
-        return this._concatValue(arg, previous);
+        return this._collectValue(arg, previous);
       }
       return arg;
     };

lib/command.js

@@ -701,7 +701,7 @@ Expecting one of '${allowedValues.join("', '")}'`);
       if (val !== null && option.parseArg) {
         val = this._callParseArg(option, val, oldValue, invalidValueMessage);
       } else if (val !== null && option.variadic) {
-        val = option._concatValue(val, oldValue);
+        val = option._collectValue(val, oldValue);
       }
 
       // Fill-in appropriate missing values. Long winded but easy to follow.

lib/option.js

@@ -162,12 +162,13 @@ class Option {
    * @package
    */
 
-  _concatValue(value, previous) {
+  _collectValue(value, previous) {
     if (previous === this.defaultValue || !Array.isArray(previous)) {
       return [value];
     }
 
-    return previous.concat(value);
+    previous.push(value);
+    return previous;
   }
 
   /**
@@ -186,7 +187,7 @@ class Option {
         );
       }
       if (this.variadic) {
-        return this._concatValue(arg, previous);
+        return this._collectValue(arg, previous);
       }
       return arg;
     };

tests/argument.variadic.test.js

@@ -101,4 +101,17 @@ describe('variadic argument', () => {
     program.parse(['one', 'two'], { from: 'user' });
     expect(passedArg).toEqual(['one', 'two']);
   });
+
+  test('when variadic has default array then specified value is used instead of default (not appended)', () => {
+    const program = new commander.Command();
+    let passedArg;
+    program
+      .addArgument(new commander.Argument('[value...]').default(['DEFAULT']))
+      .action((value) => {
+        passedArg = value;
+      });
+
+    program.parse(['one', 'two'], { from: 'user' });
+    expect(passedArg).toEqual(['one', 'two']);
+  });
 });

tests/options.variadic.test.js

@@ -162,4 +162,12 @@ describe('variadic special cases', () => {
 
     expect(program.options[0].variadic).toBeFalsy();
   });
+
+  test('when option has default array then specified value is used instead of default (not appended)', () => {
+    const program = new commander.Command();
+    program.option('-c,--comma [value...]', 'values', ['default']);
+    program.parse(['--comma', 'CCC'], { from: 'user' });
+
+    expect(program.opts().comma).toEqual(['CCC']);
+  });
 });