character-sheet/src/Modifier.js

CharacterSheet library for assembling relationships between stats and modifiers.

import Op from './operations';

/**
 * Modifies a stat definition during calculation.
 */
class Modifier {
  _description = 'This modifier has no descrition.';
  _operations = [];
  _active = true;

  currentlyModifying = null;

  get operations() {
    return this._operations;
  }

  get description() {
    return this._description;
  }

  describe(description) {
    this._description = description;
    return this;
  }

  modifies(target) {
    this._operations.push(new Op.Modifies(target));
    return this;
  }

  add(value) {
    this._operations.push(new Op.Add({ value }));
    return this;
  }

  subtract(value) {
    this._operations.push(new Op.Subtract({ value }));
    return this;
  }

  divideBy(value) {
    this._operations.push(new Op.DivideBy({ value }));
    return this;
  }

  roundUp() {
    this._operations.push(new Op.RoundUp());
    return this;
  }

  roundDown() {
    this._operations.push(new Op.RoundDown());
    return this;
  }

  calculate({ selectors = [], fn }) {
    this._operations.push(new Op.Calculate({ selectors, fn }));
    return this;
  }

  static from(modifier) {
    // make a new modifier
    let m = new Modifier();

    // import modifier from object
    m.import(modifier);

    // return modifier
    return m;
  }

  import(modifier) {
    this._description = modifier.description;
    this._operations = modifier.operations;
    this._active = modifier.active;

    return this;
  }

  export() {
    return {
      description: this._description,
      operations: this._operations.map(operation => operation.export()),
      active: this._active
    };
  }
}

export default Modifier;