TypeScript

Everything in Jinju is typed from your definitions: there are no separate interfaces to keep in sync. This page covers the types you can use to name those types yourself.

Inferring values

import { arg, flag, type InferArgs, type InferFlags, type InferFlagType } from 'jinju';

const port = flag.number({ description: 'Port' }).default(8080);
type Port = InferFlagType<typeof port>;
     
type Port = number

const flags = {
	port,
	host: flag.string({ description: 'Host' }),
};
type Flags = InferFlags<typeof flags>;
     
type Flags = {
    port: number;
    host: string | undefined;
}

const args = [arg.file({ description: 'Files' }).multiple().required()] as const;
type Args = InferArgs<typeof args>;
     
type Args = [string[]]

Type	Gives
InferFlagType<F>	The value a flag resolves to
InferArgType<A>	The value an arg resolves to
InferFlags<F>	An object of flag values, as run receives it
InferArgs<A>	A tuple of arg values, as run receives it
MergeFlags<A, B>	A with B's keys added or replaced, which is how scope and command flags combine

Sharing handlers

RunContext<Flags, Args> is the type of run's context, so a handler can be written separately from its command:

import { command, flag, type RunContext } from 'jinju';

const cleanFlags = { force: flag.boolean({ description: 'Force' }) };

const clean = ({ flags }: RunContext<typeof cleanFlags, []>) => {
	if (flags.force) console.log('forcing');
};

command({ description: 'Clean', flags: cleanFlags, run: clean });

Compile-time checks

Some mistakes are reported as type errors as well as at runtime:

• more than one .multiple() arg (CheckArgs)
• dynamic segment problems in the command tree (CheckTree)
• Standard Schemas whose input can't be a string (CheckSchemaInput)

These types resolve to an object with an ~error key that describes the problem, so the message appears in the type error.

Readable types

Types are written to show resolved values in editors, e.g. string[] | undefined rather than an alias such as Flag<…>. Every type used in a public signature is exported, so you can name anything you see. See the Types API for the full list.