range-overlap

Are 2 ranges overlap ?, demo page.

Installation

Install with npm install range-overlap then

// CommonJS
const { isRangeOverlap } = require('range-overlap')

// ES6
import { isRangeOverlap } from "range-overlap"

Example usage

// integer and floating numbers as a param
isRangeOverlap(1, 10, 2, 12) // true
isRangeOverlap(1, 10, 2, 8) // true
isRangeOverlap(100, 200, 201, 300) // false

// Date as a param
isRangeOverlap( // true
  new Date(1615452500000),
  new Date(1615452800000),
  new Date(1615452700000),
  new Date(1615452900000),
)

// array of numbers or Date(s) as a param
isRangeOverlap([1, 10], [2, 12]) // true
isRangeOverlap( // true
  [new Date(1615452500000), new Date(1615452800000)],
  [new Date(1615452700000), new Date(1615452900000)]
)

// custom type as a param
isRangeOverlap( // true
  { start: 1, end: 10 },
  { start: 2, end: 12 }
)

// support is-exclusive param
isRangeOverlap(1, 10, 10, 12, true) // false
isRangeOverlap( // false
  new Date(1615452500000),
  new Date(1615452600000),
  new Date(1615452600000),
  new Date(1615452800000),
  true
)
isRangeOverlap([1, 10], [10, 12], true) // false
isRangeOverlap( // false
  [new Date(1615452500000), new Date(1615452600000)],
  [new Date(1615452600000), new Date(1615452800000)],
  true
)
isRangeOverlap({ start: 1, end: 10 }, { start: 10, end: 12 }, true) // false

Algorithm

The detailed logic is described here, but in summary is explained below.

2 cases that will not overlapping
case1) |----range1----|  |----range2----|
       x1             x2 y1             y2

case2) |----range2----|  |----range1----|
       y1             y2 x1             x2

so isNotOverlap
= case1) or case2)
= x2 < y1 || y2 < x1

due to isOverlap
= ~isNotOverlap
= ~(x2 < y1 || y2 < x1)
= x2 >= y1 && y2 >= x1
= x1 <= y2 && y1 <= x2

CMD

npm run format && npm run lint && npm run coverage.check && npm run build
npx stryker run
npm run version

npm publish --dry-run
npm publish