Thistogram

A simple text based histogram and chart generator.

Usage

Histogram

import { histogram } from 'thistogram';

const data = [
  ['one', 1],
  ['two', 2],
  ['three', 3],
  ['four', 4],
  ['2.5', 2.5]
];
const hist = histogram(data, {
  width: 40,
  maxLabelWidth: 5,
  title: 'Numbers',
  headers: ['Label', 'Value']
});
console.log(hist);

Result:

Numbers
Label ┃                          ┃ Value
━━━━━━╋━━━━━━━━━━━━━━━━━━━━━━━━━━╋━━━━━━
one   ┃██████▌                   ┃     1
two   ┃█████████████             ┃     2
three ┃███████████████████▌      ┃     3
four  ┃██████████████████████████┃     4
2.5   ┃████████████████▎         ┃   2.5

Point-Min-Max Chart

Code:

import { histogram } from 'thistogram';

const data = [
  ['Jan', 2, 1, 6],
  ['Feb', 2, 0, 6],
  ['Mar', 4, 2, 10],
  ['Apr', 8, 4, 13],
  ['May', 12, 8, 17],
  ['Jun', 16, 12, 20],
  ['Jul', 18, 13, 22],
  ['Aug', 18, 13, 23],
  ['Sep', 14, 10, 19],
  ['Oct', 10, 6, 15],
  ['Nov', 6, 4, 10],
  ['Dec', 3, 2, 7]
];
const graph = histogram(data, {
  width: 70,
  maxLabelWidth: 5,
  title: 'Temperature Degrees C',
  type: 'point-min-max',
  headers: ['Month', 'Avg', 'Min', 'Max']
});
console.log(graph);

Result:

Temperature Degrees C
Month ┃                                              ┃ Avg ┃ Min ┃ Max
━━━━━━╋━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━╋━━━━━╋━━━━━╋━━━━
Jan   ┃  ┣━●━━━━━━━┫                                 ┃   2 ┃   1 ┃   6
Feb   ┃┣━━━●━━━━━━━┫                                 ┃   2 ┃   0 ┃   6
Mar   ┃    ┣━━━●━━━━━━━━━━━┫                         ┃   4 ┃   2 ┃  10
Apr   ┃        ┣━━━━━━━●━━━━━━━━┫                    ┃   8 ┃   4 ┃  13
May   ┃                ┣━━━━━━●━━━━━━━━━┫            ┃  12 ┃   8 ┃  17
Jun   ┃                       ┣━━━━━━━●━━━━━━━┫      ┃  16 ┃  12 ┃  20
Jul   ┃                         ┣━━━━━━━━━●━━━━━━━┫  ┃  18 ┃  13 ┃  22
Aug   ┃                         ┣━━━━━━━━━●━━━━━━━━━┫┃  18 ┃  13 ┃  23
Sep   ┃                    ┣━━━━━━●━━━━━━━━━┫        ┃  14 ┃  10 ┃  19
Oct   ┃            ┣━━━━━━━●━━━━━━━━┫                ┃  10 ┃   6 ┃  15
Nov   ┃        ┣━━━●━━━━━━━┫                         ┃   6 ┃   4 ┃  10
Dec   ┃    ┣━●━━━━━━━┫                               ┃   3 ┃   2 ┃   7

Simple Histogram

Code:

import { simpleHistogram } from 'thistogram';

const data = [
  ['jan', [5, 7, 9, 12]],
  ['feb', [13, 10, 8, 15]],
  ['mar', [14, 11, 9, 16]],
  ['apr', [17, 15, 22, 18]]
];

function calcAvg(arr) {
  return arr.reduce((a, b) => a + b, 0) / arr.length;
}

function table() {
  const lines = [];
  const allTemps = data.flatMap(([, d]) => d);
  const tempMax = Math.max(...allTemps);
  const tempMin = Math.min(...allTemps);
  const tempRange = tempMax - tempMin;
  const margin = tempRange * 0.1;
  const graphMin = Math.floor(tempMin - margin);
  const graphMax = Math.ceil(tempMax + margin);
  lines.push('| Month | Avg |  Min |  Max | Graph |');
  lines.push('|-------|----:|-----:|-----:|-------|');
  for (const [month, monthData] of data) {
    const avg = calcAvg(monthData);
    const min = Math.min(...monthData);
    const max = Math.max(...monthData);
    const histo = simpleHistogram(monthData, graphMin, graphMax);
    lines.push(`| ${month} | ${avg.toFixed(1)} | ${min} | ${max} | \`${histo}\` |`);
  }
  lines.push('');
  lines.push('The table above shows the average, minimum, and maximum temperature for each month.');
  const trendGraph = simpleHistogram(allTemps, graphMin, graphMax);
  lines.push('');
  lines.push(`Weekly Trend: \`${trendGraph}\``);
  return lines.join('\n');
}

console.log(table());

Result:

Month	Avg	Min	Max	Graph
jan	8.3	5	12	▁▂▃▄
feb	11.5	8	15	▄▃▂▅
mar	12.5	9	16	▅▄▃▅
apr	18.0	15	22	▆▅█▆

The table above shows the average, minimum, and maximum temperature for each month.

Weekly Trend: ▁▂▃▄▄▃▂▅▅▄▃▅▆▅█▆

Examples

Sine
0  ┃██▊                ┃  0.00
1  ┃█████▌             ┃  0.17
2  ┃████████▎          ┃  0.34
3  ┃██████████▉        ┃  0.50
4  ┃█████████████▏     ┃  0.64
5  ┃███████████████▏   ┃  0.77
6  ┃████████████████▊  ┃  0.87
7  ┃██████████████████ ┃  0.94
8  ┃██████████████████▊┃  0.98
9  ┃███████████████████┃  1.00
10 ┃██████████████████▊┃  0.98
11 ┃██████████████████ ┃  0.94
12 ┃████████████████▊  ┃  0.87
13 ┃███████████████▏   ┃  0.77
14 ┃█████████████▏     ┃  0.64
15 ┃██████████▉        ┃  0.50
16 ┃████████▎          ┃  0.34
17 ┃█████▌             ┃  0.17
18 ┃██▊                ┃  0.00
19 ┃▏                  ┃ -0.17