1.js

const d3 = { svg: { axis: d3axis } };
function noop(x) { console.log('called with', x); return d3axis(); }
function d3axis() { return { scale: noop, range: noop } }

class Axis {
  constructor(obj) {
    this.props = obj || {};
  }
  
  render() {
    let a = new d3.svg.axis();
    for(let key in this.props) {
      if(this.props.hasOwnProperty(key) && typeof a[key] === 'function') {
        a = a[key].call(a, this.props[key]);
      }
    }
    return a;
  }
}

var myAxis = new Axis({
  scale: 1,
  range: 2,
  color: '#000'
});
myAxis.render();