JQuery Terminal - Optional parameters in commands

Question

JQuery Terminal - Optional parameters in commands

344 Views Asked by Terry Wray At 04 April 2025 at 23:36

I want to accept optional parameters when creating a function to handle a command in the JQuery Terminal plug-in.

eg.

Foo -> returns a list of Foo's

Foo 1234 -> returns details of Foo 1234 only

Foo Active -> returns a list of Active Foo's

However, if I make my function header like this:

Foo: function() { ... }

...and then issue the command...

Foo 1234

...JQuery Terminal complains "[Arity] Wrong number of arguments. Function 'Foo' expects 0 got 1!".

The same goes for...

Foo: function(p1) { ... }

The command...

Foo

...causes JQuery Terminal to respond with "[Arity] Wrong number of arguments. Function 'Foo' expects 1 got 0!".

Original Q&A

There are 2 best solutions below

**Akshat** · Answer 1

A good workaround is to use a have a parameter but inside the function use an if-else statement to execute code when no parameter is passed, with checkArity: false in options.

Take this for example:

help: name => {
            if (!name) main.echo("For more information on a specific command, type help 'command-name'.");
            else switch (name) {
                    default:
                        main.error("Unknown flag or command: " + name);
                        break;
                    case "broadcast":
                        main.echo("Broadcasts the message to all users.");
                        break;
                    case "connect":
                        main.echo("Connects the terminal to server for chatting.");
                        break;
                    case "disconnect":
                        main.echo("Disconnects the terminal from server.");
                        break;
                    case "help":
                        main.echo("Provides full information for terminal commands.");
                        break;
            }
        }

**Terry Wray** · Answer 2

Here's how I implemented jcubic's response:

<body>
<script>
$('body').terminal({
    dostuff: function(...rawArgs) {
        if (typeof rawArgs[0] === "undefined") {
            //no arguments supplied. do the default action.
            this.echo('Thanks for running the dostuff command!');
        } 
        else {
            //at least one argument supplied
            //change all args to lowercase
            const lowerArgs = rawArgs.map(element => {
                return element.toLowerCase();
            });

        lowerArgs.forEach(myCustomArgProcessor);

        //..more custom command handling goes here
        }
    }
}, 
{checkArity:false, greetings:'Welcome message goes here\n'}
    //checkArity:false 
        //This directs JQuery Terminal to allow a different number of arguments than what the handler function expects.
        //The purpose of this is to enable function overloading, enabling commands to be used naked or with multiple parameters.
    //greetings:<text>
        //This is the greeting that shows when JQuery Terminal starts up.
);
</script>
</body>

JQuery Terminal - Optional parameters in commands

There are 2 best solutions below

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