Organize your CLI app around menu selections.

This function displays a menu on the screen, waits for the user to type a key to make a selection, and then calls the function for the selected menu item.

Example

const menu = require(`./index.js`)

menu({
	menu_items: [{
		key: `l`,
		name: `lol`,
		action: () => console.log(`Yeah, laugh it up!`),
	}, {
		key: `t`,
		name: `Tell me the time`,
		action: async() => {
			console.log(`The time is`, new Date().toLocaleTimeString())
			await new Promise(resolve => setTimeout(resolve, 1500))
			console.log(`...and now it's`, new Date().toLocaleTimeString())
		},
	}, {
		key: `m`,
		name: `Check out a different menu`,
		action: () => menu({
			title: `BEHOLD THE SUBMENU`,
			menu_items: [{
				key: `j`,
				name: `Tell me a joke`,
				action: () => console.log(`This library has no eunuch testes`),
			}, {
				key: `b`,
				name: `Go back`,
				action: ({ back }) => back(),
			}],
		}),
	}, {
		key: `q`,
		name: `quit`,
		action: ({ back }) => back(),
	}],
}).then(() => {
	console.log(`👋`)
})

API

The menu function takes an object with three properties.

menu({ title = `Menu`, menu_items, display_menu = default_display_menu })

• title: A label to display above the menu items
• menu_items: an array of objects representing the menu items
  • key: a single-character string representing the key the user will press to select the item
  • name: the string to display for the menu item
  • action: the function to call when the user selects the menu item
• display_menu: optional function that will be called when the menu needs to be displayed

The menu function returns a promise that will resolve once the user backs out of the menu.

action({ back })

The action function may return a promise.

Once the promise resolves, the menu will be displayed again.

back is a function. If you call it, the menu promise will resolve after the action function finishes.

Whatever value the action function returns will be used as the resolve value for the menu's promise.

display_menu({ title, menu_items })

Defaults to:

const menu_width = 80
const default_display_menu = ({ title, menu_items }) => {
	if (title.length <= menu_width - 4) {
		const title_with_spaces = ` ` + title + ` `
		const dashes_on_left = Math.floor((menu_width - title_with_spaces.length) / 2)
		const title_with_dashes_on_left = title_with_spaces.padStart(title_with_spaces.length + dashes_on_left, `-`)
		const display_title = title_with_dashes_on_left.padEnd(menu_width, `-`)
		console.log(display_title)
	} else {
		console.log(title)
	}
	menu_items.forEach(
		({ key, name }) => console.log(key, `:`, name),
	)
}

License

WTFPL