@thi.ng/interceptors/interceptors.js

Interceptor based event bus, side effect & immutable state handling

import { getInUnsafe } from "@thi.ng/paths/get-in";
import { defSetterUnsafe } from "@thi.ng/paths/setter";
import { defUpdaterUnsafe } from "@thi.ng/paths/updater";
import {
  FX_CANCEL,
  FX_DISPATCH,
  FX_DISPATCH_NOW,
  FX_STATE
} from "./api.js";
const trace = (_, e) => console.log("event:", e);
const forwardSideFx = (fxID) => (_, [__, body]) => ({ [fxID]: body !== void 0 ? body : true });
const dispatch = (event) => () => ({
  [FX_DISPATCH]: event
});
const dispatchNow = (event) => () => ({
  [FX_DISPATCH_NOW]: event
});
const snapshot = (id = "history") => (_, __, ___, ctx) => ctx[id].record();
const ensurePred = (pred, err) => (state, e, bus, ctx) => !pred(state, e, bus, ctx) ? {
  [FX_CANCEL]: true,
  ...err ? err(state, e, bus, ctx) : null
} : void 0;
const __eventPathState = (state, path, e) => getInUnsafe(state, path ? path(e) : e[1]);
const ensureStateLessThan = (max, path, err) => ensurePred((state, e) => __eventPathState(state, path, e) < max, err);
const ensureStateGreaterThan = (min, path, err) => ensurePred((state, e) => __eventPathState(state, path, e) > min, err);
const ensureStateRange = (min, max, path, err) => ensurePred((state, e) => {
  const x = __eventPathState(state, path, e);
  return x >= min && x <= max;
}, err);
const ensureParamRange = (min, max, value, err) => ensurePred((_, e) => {
  const x = value ? value(e) : e[1];
  return x >= min && x <= max;
}, err);
const valueSetter = (path, tx) => {
  const $ = defSetterUnsafe(path);
  return (state, [_, val]) => ({ [FX_STATE]: $(state, tx ? tx(val) : val) });
};
const valueUpdater = (path, fn) => {
  const $ = defUpdaterUnsafe(path, fn);
  return (state, [_, ...args]) => ({ [FX_STATE]: $(state, ...args) });
};
export {
  dispatch,
  dispatchNow,
  ensureParamRange,
  ensurePred,
  ensureStateGreaterThan,
  ensureStateLessThan,
  ensureStateRange,
  forwardSideFx,
  snapshot,
  trace,
  valueSetter,
  valueUpdater
};