patrik-csak/BB26

# BB26

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BB26 is a JavaScript library for working with [bijective base-26](https://en.wikipedia.org/wiki/Bijective_numeration#The_bijective_base-26_system) (BB26) numbers

## What is bijective base-26 numeration?

You’re probably familiar with BB26 numeration. It’s used for spreadsheet columns, license plate serials, and (probably?) more

Here’s an example of decimal (base-10) numbers (the numbers you use every day to count things) compared to their corresponding BB26 numbers:

```
Decimal: | 1 | 2 | 3 | … | 24 | 25 | 26 | 27 | 28 | 29 | …
   BB26: | A | B | C | … |  X |  Y |  Z | AA | AB | AC | …
```

## Install

> [!IMPORTANT]
>
> This package is a native ECMAScript Module (ESM). If your project is not ESM, read [Sindre Sorhus’s **Pure ESM package** article](https://gist.github.com/sindresorhus/a39789f98801d908bbc7ff3ecc99d99c).

```shell
npm install bb26
```

## API

### `increment()`

```typescript
function increment(string: string): string;
```

Increments a bijective base-26 string by one numeral

```javascript
import { increment } from "bb26";

increment("A");  // 'B'
increment("Z");  // 'AA'
increment("AA"); // 'AB'
```

### `random()`

```typescript
function random(upper: string): string;
function random(lower: string, upper: string): string;
```

Produces a random string between the inclusive `lower` and `upper` bounds. If only one argument is provided, a string between `'A'` and the given string is returned.

```javascript
import { random } from "bb26";

random("AAA");         // 'NE'
random("AAA", "AAAA"); // 'KXZ'
```

### `range()`

```typescript
function range(end: string): string[];
function range(start: string, end: string): string[];
```

Creates an array of bijective base-26 numerals progressing from `start` up to, but not including, `end`. If `end` is not specified, it's set to `start` with `start` then set to `'A'`.

```javascript
import { range } from "bb26";

range("B");       // ['A']
range("C");       // ['A', 'B']
range("B", "C");  // ['B']
range("B", "D");  // ['B', 'C']
range("Z", "AC"); // ['Z', 'AA', 'AB']
```

### `toBb26()`

```typescript
function toBb26(number: number): string;
```

Converts a decimal number to a bijective base-26 string

```javascript
import { toBb26 } from "bb26";

toBb26(1);  // 'A'
toBb26(2);  // 'B'
toBb26(26); // 'Z'
toBb26(27); // 'AA'
toBb26(28); // 'AB'
```

### `toDecimal()`

```typescript
function toDecimal(string: string): number;
```

Converts a bijective base-26 string to a decimal number

```javascript
import { toDecimal } from "bb26";

toDecimal("A");  // 1
toDecimal("B");  // 2
toDecimal("Z");  // 26
toDecimal("AA"); // 27
toDecimal("AB"); // 28
```