Slide 1

Slide 1 text

add superpowers to your React components with ES7 decorators

Slide 2

Slide 2 text

javascript architect @ practo @siddharthkp

Slide 3

Slide 3 text

ES7 decorators stage 2 https://tc39.github.io/proposal-decorators

Slide 4

Slide 4 text

https://babeljs.io/docs/plugins/transform-decorators/ npm install babel-plugin-transform-decorators-legacy --save

Slide 5

Slide 5 text

but, first template literals ES 6 Classes arrow functions

Slide 6

Slide 6 text

const firstName = 'siddharth' const lastName = 'kshetrapal' const fullName = firstName + ' ' + lastName Template literals

Slide 7

Slide 7 text

const firstName = 'siddharth' const lastName = 'kshetrapal' const fullName = firstName + ' ' + lastName const fullName = `${firstName} ${lastName}` Template literals

Slide 8

Slide 8 text

class Human { } ES 6 classes

Slide 9

Slide 9 text

class Human { constructor(name) { this.name = name } speak() { console.log(`Hi! My name is ${this.name}`) } } ES 6 classes

Slide 10

Slide 10 text

class Human { constructor(name) { this.name = name } speak() { console.log(`Hi! My name is ${this.name}`) } } const siddharth = new Human('siddharth') siddharth.speak() // Hi! My name is siddharth ES 6 classes

Slide 11

Slide 11 text

function log(message) { return console.log(message) } arrow functions

Slide 12

Slide 12 text

function log(message) { return console.log(message) } const log = (message) => { return console.log(message) } arrow functions

Slide 13

Slide 13 text

function log(message) { return console.log(message) } const log = message => { return console.log(message) } arrow functions

Slide 14

Slide 14 text

function log(message) { return console.log(message) } const log = message => console.log(message) arrow functions

Slide 15

Slide 15 text

function log(message) { return function () { return console.log(message) } } arrow functions

Slide 16

Slide 16 text

arrow functions function log(message) { return function () { return console.log(message) } } const log = message => { return () => { return console.log(message) } }

Slide 17

Slide 17 text

arrow functions function log(message) { return function () { return console.log(message) } } const log = message => { return () => console.log(message) }

Slide 18

Slide 18 text

arrow functions function log(message) { return function () { return console.log(message) } } const log = message => () => console.log(message)

Slide 19

Slide 19 text

ES7 decorators and we’re back https://tc39.github.io/proposal-decorators

Slide 20

Slide 20 text

class decorators class method decorators ES7 decorators

Slide 21

Slide 21 text

syntax class Title extends React.Component { render () { return
hello {this.props.name}
} }

Slide 22

Slide 22 text

class className { func() {} } syntax

Slide 23

Slide 23 text

@class-decorator class className { @class-method-decorator func() {} } syntax

Slide 24

Slide 24 text

class className { @class-method-decorator func() {} } class method decorators

Slide 25

Slide 25 text

class Human { constructor(name) { this.name = name } speak() { console.log(`Hi! My name is ${this.name}`) } }

Slide 26

Slide 26 text

class Human { constructor(name) { this.name = name } speak() { console.log(`Hi! My name is ${this.name}`) } } const siddharth = new Human('siddharth') siddharth.speak() // Hi! My name is siddharth

Slide 27

Slide 27 text

... speak() { console.log(`Hi! My name is ${this.name}`) } } const siddharth = new Human('siddharth') siddharth.speak = () => {console.log('Hi! My name is dum dum')

Slide 28

Slide 28 text

... speak() { console.log(`Hi! My name is ${this.name}`) } } const siddharth = new Human('siddharth') siddharth.speak = () => {console.log('Hi! My name is dum dum') siddharth.speak() // Hi! My name is dum dum

Slide 29

Slide 29 text

class Human { constructor(name) { this.name = name } @readonly speak() { console.log(`Hi! My name is ${this.name}`) } }

Slide 30

Slide 30 text

syntax @decorator = function const decorator = (target, key, descriptor) => { }

Slide 31

Slide 31 text

const readonly = (target, key, descriptor) => { }

Slide 32

Slide 32 text

const readonly = (target, key, descriptor) => { console.log(target, key, descriptor) } /* Human {}, 'speak', { value: [Function: speak], writable: true, enumerable: false, configurable: true } */

Slide 33

Slide 33 text

const readonly = (target, key, descriptor) => { descriptor.writable = false return descriptor }

Slide 34

Slide 34 text

@readonly speak() { console.log(`Hi! My name is ${this.name}`) } } const siddharth = new Human('siddharth') siddharth.speak = () => {console.log('Hi! My name is dum dum'} siddharth.speak() // Hi! My name is siddharth

Slide 35

Slide 35 text

class Human { constructor(name) {this.name = name} useAngular() { console.log('writing angular code') } } siddharth.writeAngular() // writing angular code

Slide 36

Slide 36 text

class Human { constructor(name) {this.name = name} @deprecate useAngular() { console.log('writing angular code') } } siddharth.writeAngular() // speak@Human: this feature will be deprecated soon! // writing angular code

Slide 37

Slide 37 text

const deprecate = (target, key, descriptor) => { }

Slide 38

Slide 38 text

const deprecate = (target, key, descriptor) => { const original = descriptor.value const name = `${target.constructor.name}.${key}` }

Slide 39

Slide 39 text

const deprecate = (target, key, descriptor) => { const original = descriptor.value const name = `${target.constructor.name}.${key}` const message = 'this feature will be deprecated soon!' descriptor.value = () => { console.log(`${name} : ${message}`) original.apply(this, arguments) } }

Slide 40

Slide 40 text

const deprecate = (target, key, descriptor) => { const original = descriptor.value const name = `${target.constructor.name}.${key}` const message = 'this feature will be deprecated soon!' descriptor.value = () => { console.log(`${name} : ${message}`) original.apply(this, arguments) } return descriptor }

Slide 41

Slide 41 text

class Human { constructor(name) {this.name = name} @deprecate useAngular() { console.log('writing angular code') } }

Slide 42

Slide 42 text

class Human { constructor(name) {this.name = name} @deprecate useAngular() { console.log('writing angular code') } } siddharth.writeAngular() // speak@Human: this feature will be deprecated soon! // writing angular code

Slide 43

Slide 43 text

class Human { constructor(name) {this.name = name} @deprecate('will be deprecated in v2.0.0') useAngular() { console.log('writing angular code') } } siddharth.writeAngular() // speak@Human: will be deprecated in v2.0.0 // writing angular code

Slide 44

Slide 44 text

syntax @decorator = function const decorator = (target, key, descriptor) => { } @decorator(argument) = higher order function const decorator = (argument) => { return (target, key, descriptor) => { } }

Slide 45

Slide 45 text

syntax @decorator = function const decorator = (target, key, descriptor) => { } @decorator(argument) = higher order function const decorator = argument => (target, key, descriptor) => { }

Slide 46

Slide 46 text

@deprecate = function const deprecate = (target, key, descriptor) => { const original = descriptor.value const name = `${target.constructor.name}.${key}` const message = 'this feature will be deprecated soon!' descriptor.value = () => { console.log(`${name} : ${message}`) original.apply(this, arguments) } return descriptor }

Slide 47

Slide 47 text

@deprecate(message) = higher order function const deprecate = message => (target, key, descriptor) => { const original = descriptor.value const name = `${target.constructor.name}.${key}` const message = 'this feature will be deprecated soon!' descriptor.value = () => { console.log(`${name} : ${message}`) original.apply(this, arguments) } return descriptor }

Slide 48

Slide 48 text

@deprecate(message) = higher order function const deprecate = message => (target, key, descriptor) => { const original = descriptor.value const name = `${target.constructor.name}.${key}` message = message || 'this feature will be deprecated soon!' descriptor.value = () => { console.log(`${name} : ${message}`) original.apply(this, arguments) } return descriptor }

Slide 49

Slide 49 text

don’t fret

Slide 50

Slide 50 text

jayphelps/core-decorators npm install core-decorators --save

Slide 51

Slide 51 text

import {readonly} from 'core-decorators' class Human { constructor(name) { this.name = name } @readonly speak() { console.log('Hi! My name is ' + this.name) } } core-decorators

Slide 52

Slide 52 text

import {time} from 'core-decorators' class Human { constructor(name) { this.name = name } @time('speak') // Human.speak-0: 1.582ms speak() { console.log('Hi! My name is ' + this.name) } } core-decorators

Slide 53

Slide 53 text

class decorators class method decorators ES7 decorators

Slide 54

Slide 54 text

@class-decorator class className { func() {} } class decorators

Slide 55

Slide 55 text

@type('mammal') class Human { constructor(name) { this.name = name console.log('I am' + this.name + ', a ' + this.type) } } /* class Dolphin class Crocodile class Fish */ class decorators

Slide 56

Slide 56 text

@type('mammal') class Human { constructor(name) { this.name = name console.log('I am' + this.name + ', a ' + this.type) } } const type = value => target => { // add {type: value} to the target class } class decorators

Slide 57

Slide 57 text

No content

Slide 58

Slide 58 text

HOC: design pattern higher order components

Slide 59

Slide 59 text

A higher-order component is a function that takes a component and returns a new (modified) component. class Label extends React.Component

Slide 60

Slide 60 text

HOC = class decorators

Slide 61

Slide 61 text

class Title extends React.Component { render () { return
hello {this.props.name}
} }

Slide 62

Slide 62 text

class Title extends React.Component { render () { return
hello {this.props.name}
} } /* </Post> /*

Slide 63

Slide 63 text

@loading('name') class Title extends React.Component { render () { return
hello {this.props.name}
} } /* </Post> /* HOC

Slide 64

Slide 64 text

@loading('name') class Title extends React.Component { render () { return
hello {this.props.name}
} } const loading = key => target => class extends React.Component { } HOC

Slide 65

Slide 65 text

@loading('name') class Title extends React.Component { render () { return
hello {this.props.name}
} } const loading = key => Component => class extends React.Component { } HOC

Slide 66

Slide 66 text

@loading('name') class Title extends React.Component { render () { return
hello {this.props.name}
} } const loading = key => Component => class extends React.Component { render () { if (this.props[key]) return loading... } } HOC

Slide 67

Slide 67 text

https://github.com/acdlite/recompose npm install recompose --save

Slide 68

Slide 68 text

import {withProps} from 'recompose' recompose

Slide 69

Slide 69 text

import {withProps} from 'recompose' @withProps({name: 'world'}) class Title extends React.Component { render () { return
hello {this.props.name}
} } recompose

Slide 70

Slide 70 text

import {withHandlers, compose} from 'recompose' const handlers = withHandlers({ onClick: props => event => mixpanel.track('Clicked', props) }) recompose

Slide 71

Slide 71 text

import {withHandlers, compose} from 'recompose' const handlers = withHandlers({ onClick: props => event => mixpanel.track('Clicked', props) }) const analytics = compose(handlers) recompose

Slide 72

Slide 72 text

import {withHandlers, compose} from 'recompose' const handlers = withHandlers({ onClick: props => event => mixpanel.track('Clicked', props) }) const analytics = compose(handlers) @analytics class Title extends React.Component { render () { return
hello {this.props.label}
} } recompose

Slide 73

Slide 73 text

import {onlyUpdateForKeys} from 'recompose' @onlyUpdateForKeys(['name']) class Title extends React.Component { render () { return
hello {this.props.name}
} } /* </Post> /* recompose

Slide 74

Slide 74 text

class Title extends React.Component { constructor () {} /* javascript constructor */ css () {} /* css constructor ? */ render () { return
hello {this.props.name}
} } rant/wish

Slide 75

Slide 75 text

No content

Slide 76

Slide 76 text

https://github.com/siddharthkp/css-constructor npm install css-constructor --save

Slide 77

Slide 77 text

import css from 'css-constructor' class Title extends React.Component { constructor () {} @css` font-size: 16px; color: {this.props.colors}; &:hover {color: #FFF;} @media {max-width: 480px} {&: font-size: 18px;} ` render () { return
hello {this.props.name}
} } css-constructor

Slide 78

Slide 78 text

@css(styles) = higher order function const css = styles => (target, key, descriptor) => { } css-constructor

Slide 79

Slide 79 text

@css(styles) = higher order function const css = styles => (target, key, descriptor) => { const prettyCSS = process(styles) // fill props, media queries, etc. const cssClass = getUniqueClassName(prettyCSS) document.head.styles += {cssClass: prettyCSS} return componentWithClassName(cssClass) } css-constructor

Slide 80

Slide 80 text

Fin.

Slide 81

Slide 81 text

@siddharthkp