node-terminal-menu

Simple menu widgets for the terminal, in JavaScript.

Two widgets are provided:

• A vertical menu, using one line per item
• A tabular menu, displaying items in a specified number of columns

The widgets expect keyboard events to be handled by the keypress module, which must be set up by the application. See the examples for more details.

Installation

As usual with node:

npm install node-terminal-menu --save

Examples

See the code examples in the tests directory. There are different example programs with different level of complexity, illustrating all the different features of the widgets.

Screenshot

The screenshot below is taken from the Nash project, which uses the table menu widget to let the user select files, directories and other elements.

Usage

Vertical menu

const { verticalMenu } = require('node-terminal-menu')

let menu = verticalMenu(config)

Config object:

• items: required - an array of strings with the list of menu items to display.
• done: required - a callback function that will be invoked when the user selects an item. The item index will be passed as a parameter to the callback.
• selection: optional - the preselected menu item. Defaults to 0.
• height: optional - maximum number of rows to display. If the height is smaller than the number of items, scrolling is used (but no scroll bar is displayed).
• decorate: optional - if present, this function will be invoked when displaying each menu item, e.g. to colorize it. It receives two parameters: the menu item string and a boolean indicating whether the item is selected or not, and returns the decorated menu item. The default implementation renders unselected menu items without decoration and selected ones in reverse color. Notice that menu items can be passed already decorated in the required items parameter, but this property is useful in case the amount of items is large and the cost of decorating all of them before opening the menu could keep the user waiting.

The call to verticalMenu returns a menu object with the following methods and properties:

• keyHandler: a key event listener that can be used to listen to keypress events. That way, when the user presses arrow keys, the listener will update the menu selection accordingly, and when the user presses return or escape, the done callback will be invoked.
• update: a method that receives a config object and updates the menu according to the new configuration.
• selection: the current selection index.

Table menu

const { tableMenu } = require('node-terminal-menu')

let menu = tableMenu(config)

Config object:

• items: required - an array of strings with the list of menu items to display.
• done: required - a callback function that will be invoked when the user selects an item. The item index will be passed as a parameter to the callback.
• columns: required - the number of columns in the table.
• columnWidth: required - the width of each column.
• selection: optional - the preselected menu item. Defaults to 0.
• height: optional - maximum number of rows to display. If the height is smaller than the number of items, scrolling is used, and an optional scrollbar can be displayed using the scrollBarCol property.
• scrollBarCol: optional - if this property is present and the height property is smaller than the total number of rows, then a vertical scroll bar is displayed at the position indicated by the value of this property.
• descs: optional - an array of description strings, corresponding to each item. If present, the selected item description will be displayed at the bottom of the table.
• descRows: optional - maximum number of description lines. If not present, it is calculated by searching inside the descriptions.
• colors: optional - an object with function properties that, if present, will be invoked to add terminal escape codes to give color to different parts of the menu.
  • item: function to colorize each menu item.
  • selectedItem: function to colorize the selected menu item
  • scrollArea: function to colorize the vertical scroll area.
  • scrollBar: function to colorize the scroll bar.
  • desc: function to colorize the item's description, if present.

The call to tableMenu returns a menu object, with the same behavior as the call to verticalMenu.

Computing the table menu layout

The columns and columnWidth properties can be provided by the user, or can be computed via the computeTableLayout helper function:

let { rows, columns, columnWidth } = computeTableLayout(items)

The function takes the array of items and computes the number of rows, columns and their width based on the number of items and the width of the longest item. Apart from the items parameter, it supports two more optional parameters:

• gap: the separation between columns - defaults to 2
• totalWidth: the table width - defaults to the number of columns of the terminal