artalar

function getCaller() {
    const stack = getStack();

    stack.shift(); // getStack
    stack.shift(); // getCaller

    // Return caller's caller
    return stack;
}

artalar

class ArrayLazy extends Array {
  _lazyQueue = [];
  map(callback) {
    this._lazyQueue.push({ type: "map", callback });
    return this;
  }
  filter(callback) {
    this._lazyQueue.push({ type: "filter", callback });
    return this;
  }

artalar

function getStack() {
    // Save original Error.prepareStackTrace
    const origPrepareStackTrace = Error.prepareStackTrace;

    // Override with function that just returns `stack`
    Error.prepareStackTrace = (_, stack) => stack;

    // Create a new `Error`, which automatically gets `stack`
    // Evaluate `err.stack`, which calls our new `Error.prepareStackTrace`
    const { stack } = new Error();

artalar

// @flow

function match<I: [*] | [*, *], O>(
  cb: (test: (predicate?: (...a: I) => any) => string) => { [string]: O | ((...a: I) => O) }
): (...a: I) => ?O {
  const predicates = {};
  function test(predicate: (...a: I) => any = () => true): string {
    const predicateName = Math.random().toFixed(5);
    predicates[predicateName] = predicate;
    return predicateName;

artalar

export const validation = store => next => action => {
  switch(action.type){
    case loginFormSubmit.type: {
      const isValid = validate(action.payload);
      if (isValid) return next(action)
      // else
      store.dispatch(loginFormIvalid())
    }
    default: return next(action)
  }

artalar

import { createStore as createReduxStore } from 'redux'
import { devToolsEnhancer } from 'redux-devtools-extension'

const redux = createReduxStore((state, { payload }) => payload, devToolsEnhancer())

export function useReduxDevTool(store) {
  store.watch(payload => redux.dispatch({ type: 'CHANGE', payload }))
}

artalar

function createMapById<PropName extends string>(
  $list: Store<{ [key in PropName]: any }[]>,
  propName: PropName,
  id: string
) {
  return $list.map(list =>
    list.reduce(
      (propByIdMap, element) => (
        (propByIdMap[element[id]] = element[propName]), propByIdMap

artalar

• 1
  • 2
    • 3
      • 4
• 5

artalar

window.onerror = function (message, source, lineno, colno, error) {
    if (typeof error === 'object' && error instanceof Error) {
        try {
            error = JSON.stringify(
                error,
                // по умолчанию поля ошибок не парсятся
                Object.getOwnPropertyNames(error),
            );
        } catch (_) {
            error = `${error.name}\n${error.message}\n${error.stack}`;

artalar

const { performance } = require('perf_hooks');

let counter = 0;
let log = [];

function logPure(log, value) {
    log.push(value);
}

function logDirty() {