intersecting-ranges/README.md

Find intersecting ranges using Marzullo algorithm

# Intersecting Ranges

Find the intersection of N intervals using a variant of [Marzullo's algorithm](https://en.wikipedia.org/wiki/Marzullo%27s_algorithm).

![diagram](https://i.imgur.com/IqhI22a.png)

## Installation

```
yarn add intersecting-ranges
```

## Usage

#### API

```
intersectingRanges(ranges [, options]);
```

#### Options

| option      | type      | default | description                                                              |
| ----------- | --------- | ------- | ------------------------------------------------------------------------ |
| `omitEmpty` | _boolean_ | true    | Don't return the original ranges if there are no overlaps                |
| `withData`  | _boolean_ | false   | Optionally store data for each range to be merged into the intersections |

Example using ranges in the picture

```js
const intersectingRanges = require("intersecting-ranges");

const ranges = [
  [1, 31], // pink
  [3, 10, { foo: 1 }], // orange
  [13, 20], // orange
  [23, 29], // orange
  [4, 15], // green
  [16, 30], // green
  [1, 7, { bar: 2 }], // blue
  [9, 24] // blue
];

intersectingRanges(ranges);
/* =>
[ [ 4, 7 ],
  [ 9, 10 ],
  [ 13, 15 ],
  [ 16, 20 ],
  [ 23, 24 ] ]
*/

intersectingRanges(ranges, { withData: true });
/* =>
[ [ 4, 7, { foo: 1, bar: 2 } ],
  [ 9, 10, { foo: 1 } ],
  [ 13, 15 ],
  [ 16, 20 ],
  [ 23, 24 ] ]
*/
```

With/without `omitEmpty` option

```js
const ranges = [[1, 31], [34, 36]];

intersectingRanges(ranges);
// []
intersectingRanges(ranges, { omitEmpty: false });
// [[1, 31], [34, 36]];
```