Questions about -v variable=value & parsing .arguments()

[cascading-jox]

Hi!

I have some questions:

1. Is it possible to do have options like -v var=val like in awk? I tried this but to no avail:

.option("-v, --variable <variable-name>=<value>", "pass variable(s) to script")

2. What is the correct way to parse arguments passed with .arguments()? Right now I use .action((_, arg) => inArg = arg) which feels like a hack. Intuitively I assumed it would be in the returned object from new Command().
3. How do you check if the argument to the option is valid? For example I have this option but any argument to the option is valid:

.option("-g, --generate <time-series|polar>")

[c4spar]

Hi @cascading-jox,

sry for late reply, i somehow missed this discussion.

1.)

Is it possible to do have options like -v var=val like in awk? I tried this but to no avail:

There are different ways to achieve your goal:

Value handler

await new Command()
  .option(
    "-v, --variable <variable-name>",
    "pass variable(s) to script",
    {
      value: (val) => {
        const [key, ...parts] = val.split("=");
        const value = parts.join("=");
        if (!value) {
          throw new ValidationError(`missing value for variable: ${val}`);
        }
        return { [key]: value };
      },
    },
  )
  .action(({ variable }) => console.log("variable:", variable))
  .parse(Deno.args);

In combination with the list type:

await new Command()
  .option(
    "-v, --variable <variable-name:string[]>",
    "pass variable(s) to script",
    {
      value: (values, prev: Record<string, string> = {}) => {
        for (const val of values) {
          const [key, ...parts] = val.split("=");
          const value = parts.join("=");
          if (!value) {
            throw new ValidationError(`missing value for variable: ${val}`);
          }
          prev[key] = value;
        }
        return prev;
      },
    },
  )
  .action(({ variable }) => console.log("variable:", variable))
  .parse(Deno.args);

In combination with the collect option:

await new Command()
  .option(
    "-v, --variable <variable-name>",
    "pass variable(s) to script",
    {
      collect: true,
      value: (val, prev: Record<string, string> = {}) => {
        const [key, ...parts] = val.split("=");
        const value = parts.join("=");
        if (!value) {
          throw new ValidationError(`missing value for variable: ${val}`);
        }
        return { ...prev, [key]: value };
      },
    },
  )
  .action(({ variable }) => console.log("variable:", variable))
  .parse(Deno.args);

Custom type

await new Command()
  .type("variable", ({ label, name, type, value }) => {
    const [key, ...parts] = value.split("=");
    const val = parts.join("=");
    if (!val) {
      throw new ValidationError(
        `${label} "${name}" must be of type "${type}", but got "${value}". Expacted value: <variable>=<value>`,
      );
    }
    return { [key]: val };
  })
  .option(
    "-v, --variable <variable-name:variable>",
    "pass variable(s) to script",
  )
  .action(({ variable }) => console.log("variable:", variable))
  .parse(Deno.args);

A custom type can be also combined with the collect option and list type but it will return an array of objects instead of a single object. But the array could be also mapped in the value handler to merge all objects into a single one.

2.)

What is the correct way to parse arguments passed with .arguments()?

Arguments supports also build-in and custom types: .arguments("<foo:number> <bar:string> <baz:my-custom-type>").

I planned to also add a .argument() method to the Command class to also add support for value handlers etc. but this is currently not implemented.

3.)

How do you check if the argument to the option is valid?

Types can be defined after the argument name separated by colon: .option("-g, --generate <name:type>")

There are a few build-in types and you can also define your custom types.
For sutom validation and value mapping you can use the value handler to manually validate the value for a specific option:

new Command()
  .option("-f, --foo <name>", "Description...", ({value}) => {
    // validate value...
    return value;
  })

or:

new Command()
  .option("-f, --foo <name>", "Description...", {
    value: ({value}) => {
      // validate value...
      return value;
    }
  })

[cascading-jox]

Thank you! Just was I was looking for!