10 javascript basics interns should know before the job

const coolFunction { return returnValue } // DON'T DO THISconst coolFunction = () => returnValue // DO THIS

let fruit = "oranges"const stringValue = `I love ${fruit}` // I love orangesconst fancier = `I love ${favFruit()?.answers?.[0]?.value || "fruit"}` // See below for what this means

let a = "something"let b = "something else"const myObject = { a, b} // same as { a: a, b: b}

let { name, email } = contact // same as name = contact.name..// or go deeper - careful as contact needs // to exist and wont be set as variable, only address willlet { contact : { address}} = person // address = person.contact.address

let stuff = [ "bye", false, 3 ]var mergedStuff = [ 1, 2, ...stuff ] // [ 1, 2, "bye", false, 3 ]

// this is a getter, ie computed type variable// learn that too!get pronouns() { // safely returns undefined rather than // blowing up with "can't get property x of undefined" return person?.details?.pronouns }// How to use it with functions and arrays:let email = getSomething()?.email// You could also do this:let { email } = getSomething();let deepThing = myFunction()?.someArrayProp?.[0]?.detail

let transformedArray = myArray.map(...)let anArray = myArray.filter(...) // filters outlet aBoolean = myArray.some(...) // .includes, .many, .everylet anItem = myArray.find(...) // returns first item

/** * Documenting stuff matters * @param thing - An important input * @returns otherthing - Clearly expected result */const gardenFunction = (thing: string) => otherthing

type Person = {  name: string;  contact: {    address: string;    email?: string;  };};const listOfPeople = [];/** * Find a person's email by name (case insensitive) * @param name - name the name. you are looking for  * @returns {Person | null} - the person's email or null if not found */const findPersonEmailByName = (name): Person | null =>  listOfPeople.find((p) => p.name.toLowerCase() == name.toLowerCase())?.contact?.email || null  null;