Salesforce Apex: Regular Expressions

Assume that you receive an email, and your task is to extract all the URLs present in the email body. Copy and paste is a tedious job, right? Using regex script, you can save yourself from the manual work.

You can refer the following code to extract all the URLs from an incoming email.

global class CreateTaskEmailExample implements Messaging.InboundEmailHandler {

  public static final String REGEX_URL = '(?i)\\b((?:[a-z][\\w-]+:(?:/{1,3}|[a-z0-9%])|www\\d{0,3}[.]|[a-z0-9.\\-]+[.][a-z]{2,4}/)(?:[^\\s()<>]+|\\(([^\\s()<>]+|(\\([^\\s()<>]+\\)))*\\))+(?:\\(([^\\s()<>]+|(\\([^\\s()<>]+\\)))*\\)|[^\\s`!()\\[\\]{};:\'".,<>?«»“”‘’]))';
 
  global Messaging.InboundEmailResult handleInboundEmail(Messaging.inboundEmail email, Messaging.InboundEnvelope env){
 
    Messaging.InboundEmailResult result = new Messaging.InboundEmailResult();
    String plainTextBody = email.plainTextBody;

    Matcher m = Pattern.compile(REGEX_URL).matcher(plainTextBody);
    while (m.find()) {
      System.debug(m.group());
    }
    ...
    ...
    ...
    
   }
}

Similarly you can use the following regex expression for email addresses:

String REGEX_EMAIL = '(?:[a-z0-9!#$%&\'*+/=?^_`{|}~-]+(?:\\.[a-z0-9!#$%&\'*+/=?^_`{|}~-]+)*|"(?:[\\x01-\\x08\\x0b\\x0c\\x0e-\\x1f\\x21\\x23-\\x5b\\x5d-\\x7f]|\\\\[\\x01-\\x09\\x0b\\x0c\\x0e-\\x7f])*")@(?:(?:[a-z0-9](?:[a-z0-9-]*[a-z0-9])?\\.)+[a-z0-9](?:[a-z0-9-]*[a-z0-9])?|\\[(?:(?:25[0-5]|2[0-4][0-9]|[01]?[0-9][0-9]?)\\.){3}(?:25[0-5]|2[0-4][0-9]|[01]?[0-9][0-9]?|[a-z0-9-]*[a-z0-9]:(?:[\\x01-\\x08\\x0b\\x0c\\x0e-\\x1f\\x21-\\x5a\\x53-\\x7f]|\\\\[\\x01-\\x09\\x0b\\x0c\\x0e-\\x7f])+)\\])';

and this one for phone numbers

String REGEX_PHONE = '(?:(?:\\+?([1-9]|[0-9][0-9]|[0-9][0-9][0-9])\\s*(?:[.-]\\s*)?)?(?:\\(\\s*([2-9]1[02-9]|[2-9][02-8]1|[2-9][02-8][02-9])\\s*\\)|([0-9][1-9]|[0-9]1[02-9]|[2-9][02-8]1|[2-9][02-8][02-9]))\\s*(?:[.-]\\s*)?)?([2-9]1[02-9]|[2-9][02-9]1|[2-9][02-9]{2})\\s*(?:[.-]\\s*)?([0-9]{4})(?:\\s*(?:#|x\\.?|ext\\.?|extension)\\s*(\\d+))?';

Javascript: Preventing Object Modification

All objects you create are extensible by default, meaning new properties can be added to the object at any time. By setting Extensible attribute on an object to false, you can prevent new properties from being added to an object. There are three different ways to accomplish this.

Preventing Extensions

One way to create a nonextensible object is with Object.preventExtensions(). In the code below, as person1 is nonextensible, the sayName() method is never added to it.

var person1 = {
   name: "Nicholas"
};

console.log(Object.isExtensible(person1));  // true

Object.preventExtensions(person1);
console.log(Object.isExtensible(person1));  // false

person1.sayName = function() {
   console.log(this.name);
};

console.log("sayName" in person1);   // false

Sealing Objects

You can use the Object.seal() method on an object to seal it. A sealed object is nonextensible, and all of its properties are nonconfigurable. That means not only can you not add new properties to the object, but you also can’t remove properties or change their type.

var person1 = {
   name: "Nicholas"
};

console.log(Object.isExtensible(person1));  // true
console.log(Object.isSealed(person1));   // false

Object.seal(person1);
console.log(Object.isExtensible(person1));  // false
console.log(Object.isSealed(person1));   // true

person1.sayName = function() {
   console.log(this.name);
};

console.log("sayName" in person1);   // false

person1.name = "Greg";
console.log(person1.name);    // "Greg"

delete person1.name;
console.log("name" in person1);   // true
console.log(person1.name);    // "Greg"

var descriptor = Object.getOwnPropertyDescriptor(person1, "name");
console.log(descriptor.configurable);   // false

Freezing Objects

If an object is frozen, you can’t add or remove properties, you can’t change properties’ types, and you can’t write to any data properties. In essence, a frozen object is a sealed object where data properties are also read-only. Frozen objects can’t become unfrozen, so they remain in the state they were in when they became frozen.

var person1 = {
   name: "Nicholas"
};
console.log(Object.isExtensible(person1));  // true
console.log(Object.isSealed(person1));   // false
console.log(Object.isFrozen(person1));   // false

Object.freeze(person1);
console.log(Object.isExtensible(person1));  // false
console.log(Object.isSealed(person1));   // true
console.log(Object.isFrozen(person1));   // true

person1.sayName = function() {
   console.log(this.name);
};

console.log("sayName" in person1);   // false

person1.name = "Greg";
console.log(person1.name);    // "Nicholas"

delete person1.name;
console.log("name" in person1);   // true
console.log(person1.name);    // "Nicholas"

var descriptor = Object.getOwnPropertyDescriptor(person1, "name");
console.log(descriptor.configurable);   // false
console.log(descriptor.writable);   // false

Javascript modules, named and default exports

Take this code where we have multiple classes defined in the same file.

class Person {
  constructor(name) {
    this.name = name;
  }

  walk() {
    console.log("Walk");
  }
}


class Teacher extends Person {
  constructor(name, degree) {
    super(name);
    this.degree = degree;
  }

  teach() {
    console.log("Teach");
  }
}

const teacher = new Teacher("John", "MA");
teacher.walk();

If we can split this code across multiple files, we call it modularity, and each file is known as module. So let's modularize this code as below so that each class will be in a separate file. The objects we define in a module are private by default. To make it public, we use the export keyword, and to use it we use the import keyword.

person.js

export class Person {
  constructor(name) {
    this.name = name;
  }

  walk() {
    console.log("Walk");
  }
}

teacher.js

import { Person } from "./person";

class Teacher extends Person {
  constructor(name, degree) {
    super(name);
    this.degree = degree;
  }

  teach() {
    console.log("Teach");
  }
}

index.js

import { Teacher } from "./Person";

const teacher = new Teacher("John", "MA");
teacher.walk();

The way we have used the export keyword, we call it named exports. To use default exports, modify person.js as follows:

export default class Person {
  constructor(name) {
    this.name = name;
  }

  walk() {
    console.log("Walk");
  }
}

and in teacher.js file, import Teacher module as below:

import Person from "./person";

...
...

Javascript: Destructuring

Destructuring Objects

With destructuring, you can extract multiple pieces of data at the same time via patterns in locations that receive data.

const person = {
   first: "John",
   last: "Doe",
   links: {
      social: {
         twitter: "https://twitter.com/john.ca",
         facebook: "https://facebook.com/johndoe"
      },
      web: {
         blog: "https://johndoe.com"
      }
   }
};

const { twitter, facebook } = person.links.social;

Rename the variables as you destructure

const { twitter: tweet, facebook: fb } = person.links.social;

Set fallback or default value

const settings = { width: 300, color: "black" };
const { width = 100, height = 100, color = "blue", fontSize = 25 } = settings;

Destructuring arrays

const details = ["John Doe", 123, "johndoe.com"];
const [name, id, website] = details;
console.log(name, id, website);

Destructuring comma separated string

const data = "Basketball,Sports,90210,23,John,Doe,cool";
const [itemName, category, sku, inventory] = data.split(",");

Destructuring into Rest - an example using rest parameter

const team = ["John", "Harry", "Sarah", "Keegan", "Riker"];
const [captain, assistant, ...players] = team;

Swapping Variables with Destructuring

let inRing = "Hulk Hogan";
let onSide = "The Rock";

[inRing, onSide] = [onSide, inRing];

To make order of arguments independent, wrap these 3 arguments in , and then pass an object in tipCalc function so that it destructures the object.

function tipCalc({ total = 100, tip = 0.15, tax = 0.13 }) {
   return total + tip * total + tax * total;
}

const bill = tipCalc({ tip: 0.2, total: 200 });
console.log(bill);

What is we don't pass anything in tipcalc?

function tipCalcDefault({ total = 100, tip = 0.15, tax = 0.13 } = {}) {
   return total + tip * total + tax * total;
}

const newBill = tipCalcDefault();
console.log(newBill);

Javascript: Spread and Rest Operators

Rest Operator

Takes multiple things and packs it into a single array

function convertCurrency(rate, ...amounts) {
   console.log(rate, amounts); // 1.5 [10, 20, 30]
}
convertCurrency(1.5, 10, 20, 30);

Can be used while destructuring into an array

const team = ["John", "Kait", "Lux", "Sheena", "Kelly"];
const [captain, assistant, ...players] = team;
console.log(captain, assistant, players);

Spread Operator

(3 dots in-front of an array or any iterable) Takes every single item from an iterable (that can loop over with for-of loop) and spread it into a new array

const featured = ["Deep Dish", "Pepperoni", "Hawaiian"];
const specialty = ["Meatzza", "Spicy Mama", "Margherita"];

const pizzas = [...featured, "veg", ...specialty];

Using above example, creating a new array fridayPizzas

const fridayPizzas = [...pizzas];

pizzas != fridayPizzas (shallow copy)

Spread string

const name = "john";
console.log([...name]); // ["j", "o", "h", "n"]

Remove an object from an array of objects

const comments = [
   { id: 209384, text: "I love your dog!" },
   { id: 523423, text: "Cuuute! 🐐" },
   { id: 632429, text: "You are so dumb" },
   { id: 192834, text: "Nice work on this wes!" }
];
const id = 632429;
const commentIndex = comments.findIndex(comment => comment.id === id);

const newComments = [
   ...comments.slice(0, commentIndex),
   ...comments.slice(commentIndex + 1)
];
console.log(newComments);

Spreading into a function

const inventors = ["Einstein", "Newton", "Galileo"];
const newInventors = ["Musk", "Jobs"];
inventors.push(...newInventors); // and not inventors.push(newInventors);
console.log(inventors);

One more example

const name = ["John", "Doe"];

function sayHi(first, last) {
   alert(`Hey there ${first} ${last}`);
}

sayHi(...name);