2023-05-15 - JavaScript

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main topics

JavaScript basics
main docs: https://developer.mozilla.org/en-US/docs/Web/JavaScript

Ruby vs JavaScript

action	Ruby	JavaScript
check type	`var.class`	`typeof(var)`
cast to int	`num.to_i`	`Number.parseInt(42, 10)`
name convention	`lower_snake_case`	`lowerCamelCase`
falsy values	`nil, false`	`false, undefined, null, 0, "", NaN`

Hash vs Object

# ruby
my_hash = { "name" => "bob", "age" => 42 }

// js
const myObj = { name: 'bob', age: 42 }

Interpolation:

# ruby
full_name = "#{first_name} #{last_name}"

// js
// known as "Template Literals" in docs
const fullName = ${firstName} ${lastName}

CRUD in arrays:

# ruby

fruits = []

fruits << "Orange"   # Create
fruits.push("Apple") # Create (also valid)

fruits[0]            # Read

fruits[0] = "Banana" # Update

fruits.delete_at(0)  # Delete

// js

const fruits = [];

fruits.push("Apple"); // Create

fruits[0];            // Read

fruits[0] = "Banana"; // Update

fruits.splice(0, 1);  // Delete (1 item at index 0)