linspace(a, b, n) from Numeric Javascript by Sébastien Loisel (https://github.com/sloisel/numeric/blob/master/src/numeric.js#L922)

index.js

numeric.linspace = function linspace(a,b,n) {
    if(typeof n === "undefined") n = Math.max(Math.round(b-a)+1,1);
    if(n<2) { return n===1?[a]:[]; }
    var i,ret = Array(n);
    n--;
    for(i=n;i>=0;i--) { ret[i] = (i*b+(n-i)*a)/n; }
    return ret;
}

some tests

describe('Linspace tests', () => {
  it('should return correct array with linspace', () => {
    expect(linspace(12, 12, 0)).toEqual([])
    expect(linspace(12, 12, 1)).toEqual([12])
    expect(linspace(12, 13, 1)).toEqual([12])
    expect(linspace(12, 13, 2)).toEqual([12, 13])
    expect(linspace(12, 24, 5)).toEqual([12, 15, 18, 21, 24])
    expect(linspace(12, 24, 4)).toEqual([12, 16, 20, 24])

    expect(linspace(12, 11, 0)).toEqual([])
    expect(linspace(12, 11, 1)).toEqual([12])
    expect(linspace(12, 11, 2)).toEqual([12, 11])

    expect(linspace(12, 1, 0)).toEqual([])
    expect(linspace(12, 1, 1)).toEqual([12])
    expect(linspace(12, 1, 2)).toEqual([12, 1])
    expect(linspace(12, 1, 5)).toEqual([12, 9.25, 6.5, 3.75, 1])
  });
});