How to use the astronomia/lib/moonphase.newMoon function in astronomia

nextNewMoon (jde) {
    let nm = this.midnight(moonphase.newMoon(toYear(jde)))
    let cnt = 0
    while (nm < jde && cnt++ < 4) {
      nm = this.midnight(moonphase.newMoon(toYear(jde + cnt * lunarOffset)))
    }
    return nm
  }

previousNewMoon (jde) {
    let nm = this.midnight(moonphase.newMoon(toYear(jde)))
    let cnt = 0
    while (nm > jde && cnt++ < 4) {
      nm = this.midnight(moonphase.newMoon(toYear(jde - cnt * lunarOffset)))
    }
    return nm
  }

previousNewMoon (jde) {
    let nm = this.midnight(moonphase.newMoon(toYear(jde)))
    let cnt = 0
    while (nm > jde && cnt++ < 4) {
      nm = this.midnight(moonphase.newMoon(toYear(jde - cnt * lunarOffset)))
    }
    return nm
  }