⭐️ What

A FP style curried vector calculation lib. (primarily for css transform rotate resize calculation)

📦 Getting Started

Installation

npm install vector-math-fp
# or
yarn add vector-math-fp

Usage

const {
    minus,
    lenOf,
    angleOf,
    rotate,
    // ...
} = require('vector-math-fp');

minus([2, 7])([3, 9]); // => [1, 2]
lenOf([3, 4]); // => 5
angleOf([1, -1]); // => -45
rotate(90, [2, 1]); // => [-1, 2]

💡 Why

It's for drag-resize-rotate and other canvas positioning calculation.

📖 Description

Rules

All curried, FP style

Vector means Array e.g. [1, 2]
Vector coordinate system is, [right, down], same as mouseEvent

Angle means Number which valid result is degree in range (-180, 180]

• degree: 180
• radian: Math.PI

Angle is clockwise, and start from [1, 0], same as css transform rotate

Rotate only support 2d vector

API

• tools
  • arrToObj (['x', 'y'], [1, 2]) => ({ x: 1, y: 2 })
  • objToArr (['x', 'y'], { x: 1, y: 2 }) => ([1, 2])
  • radianToDegree Radian => Degree
  • degreeToRadian Degree => Radian
  • formatAngle Angle => Angle // in range (-180, 180]
• math
  • minus (v1, v2) => v3
  • add (v1, v2) => v3
  • times (v1, v2) => v3
  • divide (v1, v2) => v3
  • dot (v1, v2) => Number // as len * len * cos(tha)
  • cross (v1, v2) => Number // as len * len * sin(tha)
• verctor property
  • lenOf (v) => Number
  • areaOf (v) => Number
  • ratioOf (v) => Number // as (width / height)
• angle and rotate
  • angleBetween (v1, v2) => Angle // from v1 to v2
  • angleOf (v) => Angle // from [1, 0] to v
  • vectorOf Angle => v // lenOf(v) is 1
  • rotate (Angle, v1) => v2
  • unRotate (Angle, v1) => v2 // === rotate(-Angle, v1)

Notice

minus add times divide support object directly calculation.

minus({ x: 2, y: 7 }, { x: 3, y: 9 }); // => { x: 1, y: 2 }

⌨️ Contribution

# git clone and cd into it
git clone https://github.com/seognil-lab/vector-math-fp

# npm command
npm i
npm run test:watch

📜 References

🕗 TODO