lines-js

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│ ┃ ║lines-js║                        ┃ │
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│ ┃                                   ┃ │
│ ┃ console line drawing with unicode ┃ │
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  ┃
  ┣━╸introduction
  ┣━╸getting started
  ┗━╸documentation

introduction

lines-js is a little JavaScript library to aid in drawing lines with the Unicode box drawing characters. Use it for console-based user interfaces, console art, or to build a Funciton compiler.

// tee.js
lines = require('lines-js');

tee = lines()
    .line({
        from: [0, 0],
        to: [4, 0],
        style: 'bold'
    })
    .line({
        from: [2, 0],
        to: [2, 3]
    });

console.log(tee.toString());

> node tee.js

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getting started

Install lines-js from npm with a simple

npm install --save lines-js

Start drawing lines. See the examples folder for ideas.

documentation

• input
• output

input

The interface is simple, since there aren't many options available. You pick:

• the endpoints of each line
• the line style
• the foreground and background colors

Notably, the endpoints must lie on the same row or column, since the character set only supports horizontal and vertical lines (no diagonal lines yet).

The available styles are:

• └ normal - the default
• ┗ bold
• ╚ double
• ╰ rounded

Not every style is supported for every possible intersection. The best approximation is picked if the exact character is not available.

Colors are handled by the ansi-styles module. Only 16 color mode is supported, currently.

Two methods are exposed to add lines to the view, line and box. Use box when you'd like to draw four lines with the same style for a box. Use line for complete control of each segment.

Both take the same parameters:

• from
• to
• style
• color
  • foreground
  • background

where from and to are the two coordinates defining the shape and style is the display style for the line or box. color.foreground and color.background determine the foreground and background colors, respectively.

The restrictions on from and to for lines are that they

• must share a column or a row, and
• must not be the same point.

The restriction on them for boxes is that they

• must not share a row or a column.

output

Call toString to convert the drawing to a unicode string suitable for outputting to the console. The canvas is automatically sized to include all non-negative coordinates, so the length of the result will be R * (C + 1) characters, where R is the maximum row and C the maximum column. The extra character per line is, of course, the newline.

The lines() instance is also a stream, so pipe it somewhere! See the sorting example for details.

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