conditionRegisterer.js

export const conditions = {};

/**
 * Get condition closure with pre-bound arguments.
 *
 * @param {string} name Condition name.
 * @param {Array} args Condition arguments.
 * @returns {Function}
 */
export function getCondition(name, args) {
  if (!conditions[name]) {
    throw Error(`Filter condition "${name}" does not exist.`);
  }
  const { condition, descriptor } = conditions[name];
  let conditionArguments = args;

  if (descriptor.inputValuesDecorator) {
    conditionArguments = descriptor.inputValuesDecorator(conditionArguments);
  }

  return function(dataRow) {
    return condition.apply(dataRow.meta.instance, [].concat([dataRow], [conditionArguments]));
  };
}

/**
 * Get condition object descriptor which defines some additional informations about this condition.
 *
 * @param {string} name Condition name.
 * @returns {object}
 */
export function getConditionDescriptor(name) {
  if (!conditions[name]) {
    throw Error(`Filter condition "${name}" does not exist.`);
  }

  return conditions[name].descriptor;
}

/**
 * Condition registerer.
 *
 * @param {string} name Condition name.
 * @param {Function} condition Condition function.
 * @param {object} descriptor Condition descriptor.
 */
export function registerCondition(name, condition, descriptor) {
  descriptor.key = name;
  conditions[name] = {
    condition, descriptor
  };
}