warrenlalata

numeric only
/^\d+$/
 
 
alphanumeric, dash and underscore with space
/^[a-z\d\-_\s]+$/i


detect non alphanumeric chars
/[^a-zA-Z\d]/

warrenlalata

import React, { Component } from 'react';
import {
  View,
  Text,
  StyleSheet,
  Platform,
  Button,
  ScrollView,
  InputAccessoryView,
  KeyboardAvoidingView,

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import {
  HeaderHeightContext
} from "@react-navigation/stack"; <
HeaderHeightContext.Consumer > {
    headerHeight => ( <
      KeyboardAvoidingView {
        ...(Platform.OS === "ios" ? {
          behavior: "padding"
        } : {})
      }

warrenlalata

gem "devise_custom_authenticatable"

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/**
 * Masks Input with thousand separator
 *
 * @param {string} amount - Amount
 * @return {string} Masked Amount
 *
 * @example
 * formatAmount("1000") // 1,000
 */
export function formatAmount(amount) {

warrenlalata

Open psql terminal
psql -U postgres -h localhost

Create database
create database dbname;

List databases
\l

Create user to work with db create

warrenlalata

import React, { Component } from "react";
import { Field } from "redux-form";
import PropTypes from "prop-types";
import FormControlLabel from "@material-ui/core/FormControlLabel";
import Checkbox from "@material-ui/core/Checkbox";

export default class CheckboxGroup extends Component {
  static propTypes = {
    options: PropTypes.arrayOf(
      PropTypes.shape({

warrenlalata

knex init
edit knexfile.js
in migration object, add directory property:
with 'db/migrations'

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# Development
DEV_DB_USERNAME=root
DEV_DB_PASSWORD=yourdbpassword
DEV_DB_NAME=apollo_development
DEV_DB_HOSTNAME=localhost


# Test
TEST_DB_USERNAME=root
TEST_DB_PASSWORD=yourdbpassword

warrenlalata

Transactions

As your business logic gets complex you may need to implement transactions. The classic example is a bank funds transfer from account A to account B. If the withdrawal from account A fails then the deposit to account B should either never take place or be rolled back.

Basics

All the complexity is handled by ActiveRecord::Transactions. Any model class or instance has a method named .transaction. When called and passed a block, that block will be executed inside a database transaction. If there's an exception raised, the transaction will automatically be rolled back.

Example