@jvitela/recompute/lib/hooks.js

Selector functions based on Observable and Computed values.

"use strict";

exports.__esModule = true;
exports.useComputation = void 0;

var _react = require("react");

var _reactRedux = require("react-redux");

var refsCount = 0;

var addRef = function addRef(selector) {
  if (!selector.refIds) {
    selector.refIds = [];
  }

  selector.refIds.push(++refsCount);
  return refsCount;
};

var removeRef = function removeRef(selector, refId) {
  if (!selector.refIds) {
    return;
  }

  selector.refIds = selector.refIds.filter(function (id) {
    return id !== refId;
  });

  if (selector.refIds.length === 0) {
    // console.log("clearing cache");
    selector.clearCache();
  }
};
/**
 * Wrapper around useSelector that keeps reference count per component instance
 *  in order to automatically clear the cache when all components using
 *  the selector are unmounted.
 * 
 * @param Function selector 
 * @param  {...any} args 
 */


var useComputation = function useComputation(selector) {
  for (var _len = arguments.length, args = new Array(_len > 1 ? _len - 1 : 0), _key = 1; _key < _len; _key++) {
    args[_key - 1] = arguments[_key];
  }

  var ref = (0, _react.useRef)();

  if (!ref.current) {
    ref.current = addRef(selector);
  }

  (0, _react.useEffect)(function () {
    var refId = ref.current;
    return function () {
      return removeRef(selector, refId);
    };
  }, [selector]);
  var result = (0, _reactRedux.useSelector)(function (state) {
    return selector.withState(state).apply(null, args);
  }); //   console.log(`Recomputations: ${selector.recomputations()}`);

  return result;
};

exports.useComputation = useComputation;