🍬 Syntactic sugar 

Diabetes alert 🚨

MAYA SHAVIN

Syntactic sugar - Diabetes alert

What's it about

  • 🍫  Syntactic Sugar WHAT ?
  • 🤤  Sugar is sweet...
  • 🤢  ... until it becomes too much
  • 🚀️  Handle with CARE

Syntactic sugar - Diabetes alert

Me as 👩‍💻

👩‍💻 Senior Frontend Developer @ Cloudinary

👩‍🔬 Writer @FrontEndWeekly

👩‍💼 Portfolio: https://www.mayashavin.com

@MayaShavin

👩‍💻 Founder of @VueJSIsrael

Syntactic sugar - Diabetes alert

What is Syntactic sugar?

Syntactic sugar - Diabetes alert

for (let i = 0; i < someArr.length; i++) {
    const elem = someArr[i];

    //Do something
}
someArr.forEach(element => { 
    //do something 
})
const filtered = someArr.filter(element => {
    return matchCondition(element)
));
const filtered = someArr.map(element => {
    return { isMap: true, id: element.id }
));

It's NOT JUST syntactic sugar

Syntactic sugar - Diabetes alert

impler

S

sability

U

ood Code

G

lternative

A

eadability

R

Syntactic sugar - Diabetes alert

When it's sweet...

let it be constant sweet 🤤

Syntactic sugar - Diabetes alert

LESS code

More CONCISE

FASTER

respectively

CLEARER

const banana = 'b' + 'a' + + 'a' + 'a';
const banana = `ba${fillme}a`
const hasExpression = expression ? true : false
const hasExpression = !!expression
if (object && object.child && object.child.property) {}
if (object?.child?.property) {}
const myAwesomeArr = new Array();
const myAwesomeArr = [];

Syntactic sugar - Diabetes alert

const result = []

for(let i = 0; i < data.length; i++){
  const x = data[i];
  
  if (x % 2=== 0) {
    result.push(x)
  }
}
const isEven = number => number % 2 === 0
const result = data.filter(isEven)
const myValue = inputValue || 'defaultValue';
let myValue = 'defaultValue'

if (inputValue) {
    myValue = inputValue
}

Syntactic sugar - Diabetes alert

sweet

Too

to

handle

🤢

Syntactic sugar - Diabetes alert

const flatternArr = (arr) => arr.reduce(
			         (flatten, original) => flatten.concat(Array.isArray(original) 
                                                         ? flatternArr(original) 
                                                         : original), 
                                 []);
const reducer = (flatten, original) => flatten.concat(Array.isArray(original) 
                                                         ? flatternArr(original) 
                                                         : original);

const flatternArr = (arr) => arr.reduce(reducer, []);
function flatten(arr){
    var reducer = (flatten, original) => flatten.concat(Array.isArray(original) 
                                                        ? flatten(original) : original);
    
    return arr.reduce(reducer, []);
}
const emitEvent = (eventId, ...params) => {
    ((callback) => setTimeout(() => callback(...params)))(events[eventId])
}

Syntactic sugar - Diabetes alert

🤷‍♀️

Less code !==  More readability

Syntactic sugar - Diabetes alert

Filtering & mapping an array

const mappedData = data
                   .filter(x => isEven(x))
                   .map(x => x * 2);
const mappedData = [];

for (let i = 0; i < data.length; i++) {
    const x = data[i];

    if (isEven(x)) {
        mappedData.push(x * 2);
    }
}

O(n)

O(n)

                   .reduce(x => x * 2)
// And so on...

Syntactic sugar - Diabetes alert

It's O(n) but NOT O(n)

n = 100000
x 100000
data.filter()
x 100000
filtered.map()

new array created

new array created

x 100000

new array created

modify that array

for(...)

Syntactic sugar - Diabetes alert

🤷‍♀️

Concise code !==  Better performance

Syntactic sugar - Diabetes alert

Spread them all

const childObj = {
    ...momObj,
    ...dadObj
}
const momObj = {
    traitA: true,
    traitB: false,
    uselessInfo: 'uselessInfo',
    //...
}
const dadObj = {
    traitA: false,
    traitB: true,
    //...
}

traitA from momObj?

traitB from dadObj?

without uselessInfo?

Syntactic sugar - Diabetes alert

🤷‍♀️

Clearer !==  Less overhead

Syntactic sugar - Diabetes alert

Babel? 😳

Syntactic sugar - Diabetes alert

const sumUp = (...numbers) => {
    let sum = 0;
    for(const number of numbers) {
        sum += number;
    }
    return sum;
}
"use strict";

var sumUp = function sumUp() {
  for (var _len = arguments.length, 
        numbers = Array(_len), _key = 0; 
        _key < _len; _key++) {
    numbers[_key] = arguments[_key];
  }

  var sum = 0;
  for (var _iterator = numbers, 
      _isArray = Array.isArray(_iterator),
      _i = 0, 
      _iterator = _isArray ? _iterator : _iterator[Symbol.iterator]();;) {
    var _ref;

    if (_isArray) {
      if (_i >= _iterator.length) break;
      _ref = _iterator[_i++];
    } else {
      _i = _iterator.next();
      if (_i.done) break;
      _ref = _i.value;
    }

    var number = _ref;

    sum += number;
  }
  return sum;
};

>9.x

Syntactic sugar - Diabetes alert

function Point(x, y) {
  this.x = x;
  this.y = y;
}

var p = new Point(11, 22);
var q = new Point(33, 44);

q.z = 55;

Syntactic sugar - Diabetes alert

The hidden class

Syntactic sugar - Diabetes alert

Handle with CARE

Syntactic sugar - Diabetes alert

heck check check

C

sk for review

A

ead

R

xplicity

E

Syntactic sugar - Diabetes alert

Thank you 🤟

Syntactic sugar, diabetes alert

By Maya Shavin

Syntactic sugar, diabetes alert

JavaScript starting with ES6 offered a lot of new syntax and features. Most helps saving lines of code needs, while improves code readability and reduces the learning curve for the language. Yet usage of these syntax without considering consequences nor situation can bring the exact opposite result. In this session, we will discuss about these pitfalls, and how to develop more proactive coding habit .

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