Introduction to JavaScript

If you don’t know any JavaScript, this is a quick 5-minute course explaining most things you will need to understand.

Full JavaScript Docs

If you need a more in-depth explanation, you can look up anything on developer.mozilla.org, everything except for the DOM.

Semicolons

Semicolons in JavaScript are optional comparing to Java and Groovy, as in JavaScript we have automatic semicolon insertions.

Logging

// Display's word hello in browser console.
console.log('hello');

// Show in the console object data from crm
const payload = await crmManager.getPayload();
console.log(`This is data from the payload {payload}`);

Variables

To define a variable, use the let or const keyword. Don’t use var as it is a global variable and can conflict with interceptor, app and CRM.

let someString = 'some-string'

let someNumber = 69

let someBool = true

const array = ['string', 69, true]

const object = {
  key: 'value',
  'key-word': 'value',
}

Flow control

//if else

let i = 0;
if (i < 0) {
  console.log("its negative");
} else if (i > 0) {
  console.log("its more than 0");
} else {
  console.log("its 0");
}

// while loop

let i = 0;

while (i < 5) {
  console.log(i);
  i++;
}

// for loop

for (let i = 0; i < 5; i++) {
  console.log(i);
}

// for of loop

const array = [0, 1, 2, 3, 4];

for (const item of array) {
  console.log(item);
}

Functions

There are multiple ways to define functions, with the function keyword or with arrow functions, also known as lambda functions in other languages.

Arrow function (lambda function):

const fn = (param1, param2) => {
  console.log(param1, param2);
}

Named function:

function fn(param1, param2) {
  console.log(param1, param2);
}

Nameless function assigned to a constant variable:

const fn = function(param1, param2) {
  console.log(param1, param2);
}

All of these functions can be invoked in the same way, like any other function:

fn('Hola', 'pricefx');

Additionally, JavaScript supports default parameter values, which can be used to provide a default value for a parameter if no value is provided when the function is called. Here's an example:

function fn(param1, param2 = 'hello') {
  console.log(param1, param2);
}

fn(); // Outputs: undefined, hello

Destructuring

Arrays

// Initialize an array with five elements
const array = [1, 2, 3, 4, 5];

// Use array destructuring to assign the first two elements to variables,
// and the rest of the elements to a new array called 'rest'
const [elem1, elem2, ...rest] = array;

// Log the values of the variables to the console
console.log(elem1, elem2, rest); // Outputs: 1, 2, [3, 4, 5]

Objects

// Initialize an object with four properties
const object = {one: 1, two: 2, three: 3, four: 4};

// Use object destructuring to assign the values of the 'one' and 'two' properties to variables,
// and the rest of the properties to a new object called 'rest'
const {one, two, ...rest} = object;

// Log the values of the variables to the console
console.log(one, two, rest); // Outputs: 1, 2, {three: 3, four: 4}

String formatting

use backticks and ${}

const string = 'pricefx'
const formatted = `Hi ${string}`
console.log(formatted) // Hi pricefx