[JS -- common libs] #JavaScript #TypeScript

snippets.js

import EventEmitter from 'emittery'

const EMITTER_EVT = 'change'

const emitter = new EventEmitter<{ [EMITTER_EVT]: string }>()

emitter.emit(EMITTER_EVT, `[in-mem]`)
const unbind = emitter.on(EMITTER_EVT, (src: string) => { ... })

        
////////////////////////////////////

import fetch_ponyfill from 'fetch-ponyfill'

const { fetch, Request, Response, Headers } = fetch_ponyfill()

////////////////////////////////////

import debounce from 'lodash/debounce'

////////////////////////////////////
/*
"memoize-one": "^5",
"@types/memoize-one": "^4",
*/
import memoize_one from 'memoize-one'
const get_derived: GetDerived = memoize_one(get_derived_unmemoized)

////////////////////////////////////

// "tiny-invariant": "^1",
import assert from 'tiny-invariant'
assert(
  typeof defaultValue !== 'undefined',
  `getFeatureFlag: a default value must be provided when querying "${featureFlagName}"!`,
)

////////////////////////////////////

// "dequal": "^2",
import { dequal as is_deep_equal } from 'dequal'
assert(is_deep_equal(eventual_state_hint, store_state), 'dispatcher: state hint = store state')

////////////////////////////////////

// https://github.com/dphilipson/typescript-string-enums
// npm i typescript-string-enums
// yarn add typescript-string-enums

import { Enum } from 'typescript-string-enums'

// tslint:disable-next-line: variable-name
export const MarkName = Enum(
  'initialBundleRequested',
  'initialBundleLoaded',
  'appStarted',
  'reactStarted',
  'userLoggedIn',
  'userAttemptedLogin'
)
export type MarkName = Enum<typeof MarkName> // eslint-disable-line no-redeclare

/////

Enum.keys(enum)
Enum.values(enum)
if (!Enum.isType(Color, colorString)) {
    throw new Error(`${colorString} is not a valid color`)