ranges-invert^2.1.50

Invert string index ranges

Install via npm

npm i ranges-invert

The default is exported, so instead of invert below, you can name the consumed function however you want.

Consume via a require():

const invert = require("ranges-invert");

or as an ES Module:

import invert from "ranges-invert";

Install as a script, via CDN

Put this in your HTML:

<script src="https://cdn.jsdelivr.net/npm/ranges-invert/dist/ranges-invert.umd.js">

Then, you’ll get a global variable rangesInvert in your Global object and you consume it like this:

const invert = rangesInvert;

This invert is your main function. See its API in the main section.

Learn more about Ranges

We have a dedicated page about Ranges. Learn more

Trivia

This program has 72 assertions in its unit tests. That's more than all unit test assertions' median (51.5) but less than geometric mean (73).

In monorepo, 2 other packages consume this package.

§ Quick Take

import { strict as assert } from "assert";
import invert from "ranges-invert";

assert.deepEqual(
  invert(
    [
      [3, 5],
      [5, 7],
    ],
    9 // string length needed to set the boundary
  ),
  [
    [0, 3],
    [7, 9],
  ]
);

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§ API

invert(arr, strLen, [opts])

Input argument	Type	Obligatory?	Description
`arrOfRanges`	Array of zero or more arrays	yes	Provide an array of ranges to invert. Ranges do not have to be sorted or merged.
`strLen`	Integer number	yes	Algorithm needs to know the length of the reference string to calculate the inverted last slice's ending index.
`opts`	Plain object	no	Optional options go here.

Output: null OR array of zero or more arrays (so-called ranges) where each consists of two or more natural number (or zero) indexes.

This package does not mutate the input array, instead it creates and returns a new array with ranges inverted.

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§ Options object

`options` object's key	Type	Obligatory?	Default	Description
`strictlyTwoElementsInRangeArrays`	Boolean	no	`false`	If set to true, all ranges must have two and only two elements, otherwise an error will be thrown. For example, input being `[ [1, 2, 'zzz'] ]` would throw (because of 3 elements), as well as `[ ['a'] ]` (1 element).
`skipChecks`	Boolean	no	`false`	If set to true, no checks will be performed. It's handy to cut corners for perf reasons when you know input ranges are clean.