property-testing-polynomial-class.js

class Polynomial {
  /**
   * @param {array} coefficients
   *   with coefficients[i] being the coefficient for X^i
   */
  constructor(coefficients) {
    // remove leading 0s, so 0x^2 + 2x + 1 becomes 2x + 1
    this._coefficients = this._trimCoefficients(coefficients);
  }

  get coefficients() {
    return this._coefficients;
  }

  evaluate(x) {
    const reducer = (y, coefficient, power) =>
      y + coefficient * Math.pow(x, power);
    return this.coefficients.reduce(reducer, 0);
  }
  //...
}