code: function init$2() {
          this.x0 = this.x0 !== undefined ? this.x0 : 0;
          this.y0 = this.y0 !== undefined ? this.y0 : 0;
          this.long0 = this.long0 !== undefined ? this.long0 : 0;
          this.lat0 = this.lat0 !== undefined ? this.lat0 : 0;
  
          if (this.es) {
              this.en = pj_enfn(this.es);
              this.ml0 = pj_mlfn(this.lat0, Math.sin(this.lat0), Math.cos(this.lat0), this.en);
          }
      }
docs: Heavily based on this tmerc projection implementation https://github.com/mbloch/mapshaper-proj/blob/master/src/projections/tmerc.js