leaflet-canvaslayer-field/spec/VectorSpec.js

A set of layers using canvas to draw ASCIIGrid or GeoTIFF files. This includes a basic raster layer (*ScalaField*) and an animated layer for vector fields, such as wind or currents (*VectorFieldAnim*)

describe('Vector', function() {
    // For reference, this is a great library: http://victorjs.org/
    let Vector = L.Vector;
    it('returns u & v values', function() {
        let vector = new Vector(0.0, 0.1);
        expect(vector.u).toEqual(0.0);
        expect(vector.v).toEqual(0.1);
    });

    it('calculates its magnitude', function() {
        let vector = new Vector(0.0, 0.1);
        expect(vector.magnitude()).toEqual(0.1);

        vector = new Vector(100, 100);
        expect(vector.magnitude()).toBeCloseTo(141.42, 2);

        // upper-right corner @ test.json
        let v = new Vector(0.215018898248672, -0.00158081843983382);
        expect(v.magnitude()).toBeCloseTo(0.215025, 6);
    });

    it('calculates its directionTo / directionFrom', function() {
        expect(new Vector(0, 1).directionTo()).toEqual(0);
        expect(new Vector(0, 1).directionFrom()).toEqual(180);

        expect(new Vector(1, 1).directionTo()).toEqual(45);
        expect(new Vector(1, 1).directionFrom()).toEqual(225);

        expect(new Vector(1, 0).directionTo()).toEqual(90);
        expect(new Vector(1, 0).directionFrom()).toEqual(270);

        expect(new Vector(1, -1).directionTo()).toEqual(135);
        expect(new Vector(1, -1).directionFrom()).toEqual(315);

        expect(new Vector(0, -1).directionTo()).toEqual(180);
        expect(new Vector(0, -1).directionFrom()).toEqual(0);

        expect(new Vector(-1, -1).directionTo()).toEqual(225);
        expect(new Vector(-1, -1).directionFrom()).toEqual(45);

        expect(new Vector(-1, 0).directionTo()).toEqual(270);
        expect(new Vector(-1, 0).directionFrom()).toEqual(90);

        expect(new Vector(-1, 1).directionTo()).toEqual(315);
        expect(new Vector(-1, 1).directionFrom()).toEqual(135);

        vector = new Vector(100, 100);
        expect(vector.directionTo()).toEqual(45);
        expect(vector.directionFrom()).toEqual(225);

        vector = new Vector(100, 0);
        expect(vector.directionTo()).toEqual(90);
        expect(vector.directionFrom()).toEqual(270);
    });
});