An essential point to remember a training course is to take notes and discuss the subject with others. That's why every day I will post on dev.to the concepts and notes that I learned the day before.
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Without further ado here is a summary of my notes for today.
Destructuring Arrays
// long version const names = ['Mike', 'Paul', 'John'] const name1 = names[0] const name2 = names[1] const name3 = names[2] // or same result with Destructuring Array const [name1, name2, name3] = names // or only get first two element const [name1, name2] = names // or only get first and third element const [name1, ,name3] = names // Destructuring from a multi returns function const sumAndMultiplication = function(num1, num2) { return [num1 + num2, num1 * num2] } const [sum, multiplication] = sumAndMultiplication(10, 10) console.log(sum, multiplication) // 20 100 // Destructuring when less value const [number1, number2] = [1] // number1 = 1, number2 = undefined // Destructuring default value const [number1 = 0, number2 = 0] = [1] // number1 = 1, number2 = 0 Destructuring Objects
const post = { id: 100, title: 'This is my Blog', description: 'This is my blog text body..', tags: ['web', 'dev', 'js'], } // Destructuring with same matching object property name const {id, title} = post // Variable name different from property name const {number: id, main: title} = post // Default value if property not present in object const {id, title, user = 1} = post // or another example const {id, title, categorie = []} = post // Assign existing variables let id = 100 let title = 'My Blog title' // use the parentheses ({id, title} = post) // Function parameters destructuring const createPost = function({id = 200, name, title}) { console.log(id) console.log(name) console.log(title) } // Pass object as parameters const obj = { name: 'Mike', title: 'New Title' } createPost(obj) // or direct createPost({name: 'Mike', title: 'New title'}) 
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