Installation
Quick Take
API — isIndexWithin()
The main function isIndexWithin() is imported like this:
It’s a function which takes three input arguments:
| Input argument | Type | Obligatory | Description |
|---|---|---|---|
indexType: Natural number Obligatory: yes | |||
index | Natural number | yes | The natural number index you’re checking |
rangesArrType: Array of zero or more arrays or nullObligatory: yes | |||
rangesArr | Array of zero or more arrays or null | yes | Array of ranges, for example, [ [1, 5], [10, 20] ] |
optsType: Plain object Obligatory: no | |||
opts | Plain object | no | Optional Options Object. |
The Optional Options Object has the following shape:
| Key | Type | Default | Description |
|---|---|---|---|
inclusiveRangeEndsType: Boolean Default: false | |||
inclusiveRangeEnds | Boolean | false | That is, do we consider 1 or 5 to be within range [1, 5]? The default answer is no, but if set to true, the answer would be yes. |
returnMatchedRangeInsteadOfTrueType: Boolean Default: false | |||
returnMatchedRangeInsteadOfTrue | Boolean | false | If set to true, instead of result true it will return the matched range. false is still used as a negative answer. It’s handy when you want to know which range it matched. |
Here are all defaults in one place for copying:
The function will return either a boolean, or the matched range (opts.returnMatchedRangeInsteadOfTrue).
If opts.returnMatchedRangeInsteadOfTrue is set to true, positive result will be the range which was matched. Negative result would be still false.
API — defaults
You can import defaults:
It's a plain object:
The main function calculates the options to be used by merging the options you passed with these defaults.
API — version
You can import version:
Example
Simple encoding using default settings:
import { isIndexWithin } from "ranges-is-index-within";
let res1 = isIndexWithin(79, [
[5, 10],
[15, 20],
[25, 30],
[35, 40],
[45, 50],
[55, 60],
[65, 70],
[75, 80], // <-- "true", - "79" would be within this range, answer is "true"
[85, 90],
[95, 100],
[105, 110],
[115, 120],
[125, 130],
]);
console.log(res1);
// > true
let res2 = isIndexWithin(31, [
[5, 10],
[15, 20],
[25, 30], // <-- "false" because "31" falls in between this and next range. It's not within.
[35, 40],
[45, 50],
[55, 60],
[65, 70],
[75, 80],
[85, 90],
[95, 100],
[105, 110],
[115, 120],
[125, 130],
]);
console.log(res2);
// > false
let res3 = isIndexWithin(
30,
[
[5, 10],
[15, 20],
[25, 30], // <-- "true" because opts.inclusiveRangeEnds=true and "30" is on the edge of the range.
[35, 40],
[45, 50],
[55, 60],
[65, 70],
[75, 80],
[85, 90],
[95, 100],
[105, 110],
[115, 120],
[125, 130],
],
{ inclusiveRangeEnds: true }
);
console.log(res3);
// > true
let res4 = isIndexWithin(
30,
[
[5, 10],
[15, 20],
[25, 30], // <-- "true" because opts.inclusiveRangeEnds=true and "30" is on the edge of the range.
[35, 40],
[45, 50],
[55, 60],
[65, 70],
[75, 80],
[85, 90],
[95, 100],
[105, 110],
[115, 120],
[125, 130],
],
{ inclusiveRangeEnds: true, returnMatchedRangeInsteadOfTrue: true }
);
console.log(res4);
// > [25, 30] <------ ! not Boolean, but the range itself.
The algorithm
We tried Binary Search algorithm but native Array.prototype.find()/Array.prototype.some() are around 85x faster.