redux-cli-logger/src/index.js

Redux logger for a node environment

'use strict'

const colors = require("colors/safe")

// gets top level keys and prints them in format
const topLevel = (obj, rightArrow) => {
  let formatted = ''
  Object.keys(obj).forEach(key => {
    if (key.length > 0) {
      formatted += `${rightArrow} ${key} `
    }
    if (obj.hasOwnProperty(key)) {
      formatted += `${JSON.stringify(obj[key])}\n`
    }
  })

  return formatted
}

const renderToConsole = (obj, rightArrow) => {
  try {
    return topLevel(obj, rightArrow)
  } catch (e) {
    return obj
  }
}

export default function createCLILogger (options) {
  const {
    downArrow = '▼',
    rightArrow = '▶',
    messageColor = 'yellow',
    prevColor = 'grey',
    actionColor = 'blue',
    nextColor = 'green',
    predicate = null,
    log = console.log,
    stateTransformer = (x) => x,
    actionTransformer = (x) => x
  } = options

  return store => next => action => {
    const {getState} = store

    if (predicate && !predicate(getState, action)) {
      return next(action)
    }

    if (typeof console === 'undefined') {
      return next(action)
    }

    const prevState = renderToConsole(stateTransformer(getState()), rightArrow)
    const actionDisplay = renderToConsole(actionTransformer(action), rightArrow)
    const returnValue = next(action)
    const nextState = renderToConsole(stateTransformer(getState()), rightArrow)
    const time = new Date()

    const h = padLeft(time.getHours(), 2, "0");
    const m = padLeft(time.getMinutes(), 2, "0");
    const s = padLeft(time.getSeconds(), 2, "0");
    const message = `${downArrow} action ${action.type} @ ${h}:${m}:${s}`

    const output = `${colors[messageColor](message)}\n` +
      `  ${colors[prevColor](`prev state\n${prevState}`)}` +
      `  ${colors[actionColor](`action\n${actionDisplay}`)}` +
      `  ${colors[nextColor](`next\n${nextState}`)}`

    log(output)
    return returnValue
  }
}

function padLeft(input, len, filler) {
  var output = ""+input;
  while (output.length < len) {
    output = filler + output;
  }
  return output;
}