├── .gitignore
├── .prettierrc.js
├── README.md
├── package.json
├── public
    ├── favicon.ico
    ├── index.html
    └── manifest.json
├── recording.mov
├── screenshot.png
├── src
    ├── App.tsx
    ├── Drag.tsx
    ├── DragContext.ts
    ├── Drop.tsx
    ├── Stack.tsx
    ├── index.css
    ├── index.tsx
    ├── react-app-env.d.ts
    ├── styles.module.css
    ├── types.ts
    └── utils.ts
├── tsconfig.json
└── yarn.lock


/.gitignore:
--------------------------------------------------------------------------------
 1 | # See https://help.github.com/articles/ignoring-files/ for more about ignoring files.
 2 | 
 3 | # dependencies
 4 | /node_modules
 5 | /.pnp
 6 | .pnp.js
 7 | 
 8 | # testing
 9 | /coverage
10 | 
11 | # production
12 | /build
13 | 
14 | # misc
15 | .DS_Store
16 | .env.local
17 | .env.development.local
18 | .env.test.local
19 | .env.production.local
20 | 
21 | npm-debug.log*
22 | yarn-debug.log*
23 | yarn-error.log*
24 | 


--------------------------------------------------------------------------------
/.prettierrc.js:
--------------------------------------------------------------------------------
1 | module.exports = {
2 |   trailingComma: 'es5',
3 |   tabWidth: 2,
4 |   semi: false,
5 |   singleQuote: true,
6 | }
7 | 


--------------------------------------------------------------------------------
/README.md:
--------------------------------------------------------------------------------
 1 | # nested-dnd
 2 | 
 3 | Proof of concept for doing a nested drag and drop in React. Features smooth,
 4 | animated drop and cancel.
 5 | 
 6 | ---
 7 | 
 8 | ### :construction: **WORK IN PROGRESS** :construction:
 9 | 
10 | At the moment this serves more as a proof of concept (or example) rather than
11 | a library-like thing.
12 | 
13 | ---
14 | 
15 | Check out a [video](https://twitter.com/tczajecki/status/1122261807249412097) on
16 | my Twitter.
17 | 
18 | <p align="center"><img src="screenshot.png"></p>
19 | 
20 | ## Features
21 | 
22 | - Allows you to drag a part of the stack with the items lying on top of the
23 |   dragged one.
24 | - Drop it on top of any other stack so the elements will smoothly migrate there.
25 | - Drop it anywhere so the elements smoothly go back to their place.
26 | 
27 | ## How it works?
28 | 
29 | - The overlaying of the cards relies on CSS transforms.
30 | - Animations are triggered
31 |   in JS via `element.animate(...)` API.
32 | - The element currently being dragged always stays on top with use of `:focus`.
33 | - Stack is a recursive component.
34 | - Drop zones are registered and passed using context API.
35 | - Changing parent stack uses waaaay too much logic bound to this example.
36 | 
37 | ## TODO
38 | 
39 | Putting it here so I won't forget.
40 | 
41 | - [x] Get rid of example-specific magic numbers from `<Drag />`.
42 | - [ ] Fix bug with dropping outside of `<Drop />` sometimes being possible.
43 | - [ ] Extract some top level API components from `<App />`.
44 | - [ ] Maybe use indexes instead of made up IDs that are mostly indexes anyway.
45 | - [ ] Rethink naming of things in a way that keeps the cards analogy but isn't
46 |       specific to it when not necessary.
47 | 
48 | ## Installation
49 | 
50 | **tl;dr**: not yet.
51 | 
52 | The only way to have fun with it is cloning the repository.
53 | 


--------------------------------------------------------------------------------
/package.json:
--------------------------------------------------------------------------------
 1 | {
 2 |   "name": "another-dnd",
 3 |   "version": "0.1.0",
 4 |   "private": true,
 5 |   "dependencies": {
 6 |     "@types/jest": "^24.0.11",
 7 |     "@types/node": "^11.13.7",
 8 |     "@types/react": "^16.8.14",
 9 |     "@types/react-dom": "^16.8.4",
10 |     "react": "^16.8.6",
11 |     "react-dom": "^16.8.6",
12 |     "react-scripts": "3.0.0",
13 |     "typescript": "^3.4.5"
14 |   },
15 |   "scripts": {
16 |     "start": "react-scripts start",
17 |     "build": "react-scripts build",
18 |     "test": "react-scripts test",
19 |     "eject": "react-scripts eject"
20 |   },
21 |   "eslintConfig": {
22 |     "extends": "react-app"
23 |   },
24 |   "browserslist": {
25 |     "production": [
26 |       ">0.2%",
27 |       "not dead",
28 |       "not op_mini all"
29 |     ],
30 |     "development": [
31 |       "last 1 chrome version",
32 |       "last 1 firefox version",
33 |       "last 1 safari version"
34 |     ]
35 |   }
36 | }
37 | 


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/public/favicon.ico:
--------------------------------------------------------------------------------
https://raw.githubusercontent.com/tchayen/nested-dnd/cf52375dfd1f0697309d88bc59be6817ca45d232/public/favicon.ico


--------------------------------------------------------------------------------
/public/index.html:
--------------------------------------------------------------------------------
 1 | <!DOCTYPE html>
 2 | <html lang="en">
 3 |   <head>
 4 |     <meta charset="utf-8" />
 5 |     <link rel="shortcut icon" href="%PUBLIC_URL%/favicon.ico" />
 6 |     <meta name="viewport" content="width=device-width, initial-scale=1" />
 7 |     <meta name="theme-color" content="#000000" />
 8 |     <!--
 9 |       manifest.json provides metadata used when your web app is installed on a
10 |       user's mobile device or desktop. See https://developers.google.com/web/fundamentals/web-app-manifest/
11 |     -->
12 |     <link rel="manifest" href="%PUBLIC_URL%/manifest.json" />
13 |     <!--
14 |       Notice the use of %PUBLIC_URL% in the tags above.
15 |       It will be replaced with the URL of the `public` folder during the build.
16 |       Only files inside the `public` folder can be referenced from the HTML.
17 | 
18 |       Unlike "/favicon.ico" or "favicon.ico", "%PUBLIC_URL%/favicon.ico" will
19 |       work correctly both with client-side routing and a non-root public URL.
20 |       Learn how to configure a non-root public URL by running `npm run build`.
21 |     -->
22 |     <title>React App</title>
23 |   </head>
24 |   <body>
25 |     <noscript>You need to enable JavaScript to run this app.</noscript>
26 |     <div id="root"></div>
27 |     <!--
28 |       This HTML file is a template.
29 |       If you open it directly in the browser, you will see an empty page.
30 | 
31 |       You can add webfonts, meta tags, or analytics to this file.
32 |       The build step will place the bundled scripts into the <body> tag.
33 | 
34 |       To begin the development, run `npm start` or `yarn start`.
35 |       To create a production bundle, use `npm run build` or `yarn build`.
36 |     -->
37 |   </body>
38 | </html>
39 | 


--------------------------------------------------------------------------------
/public/manifest.json:
--------------------------------------------------------------------------------
 1 | {
 2 |   "short_name": "React App",
 3 |   "name": "Create React App Sample",
 4 |   "icons": [
 5 |     {
 6 |       "src": "favicon.ico",
 7 |       "sizes": "64x64 32x32 24x24 16x16",
 8 |       "type": "image/x-icon"
 9 |     }
10 |   ],
11 |   "start_url": ".",
12 |   "display": "standalone",
13 |   "theme_color": "#000000",
14 |   "background_color": "#ffffff"
15 | }
16 | 


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/recording.mov:
--------------------------------------------------------------------------------
https://raw.githubusercontent.com/tchayen/nested-dnd/cf52375dfd1f0697309d88bc59be6817ca45d232/recording.mov


--------------------------------------------------------------------------------
/screenshot.png:
--------------------------------------------------------------------------------
https://raw.githubusercontent.com/tchayen/nested-dnd/cf52375dfd1f0697309d88bc59be6817ca45d232/screenshot.png


--------------------------------------------------------------------------------
/src/App.tsx:
--------------------------------------------------------------------------------
  1 | import React, { useReducer } from 'react'
  2 | import { ID, Card, Dimensions } from './types'
  3 | import styles from './styles.module.css'
  4 | import Stack from './Stack'
  5 | import { split, oneOf, friends } from './utils'
  6 | import DragContext, { defaultContext } from './DragContext'
  7 | 
  8 | type CardStack = {
  9 |   id: ID
 10 |   cards: Array<Card>
 11 | }
 12 | 
 13 | type State = {
 14 |   stacks: Array<CardStack>
 15 | }
 16 | 
 17 | type Action = { type: 'drop'; stackId: ID; cardId: ID }
 18 | 
 19 | type BoxProps = {
 20 |   color: string
 21 | }
 22 | 
 23 | const Box = ({ color }: BoxProps) => (
 24 |   <div className={styles.box} style={{ backgroundColor: color }} />
 25 | )
 26 | 
 27 | const length = 7
 28 | const maxRgb = 255
 29 | 
 30 | const indexToPink = (i: number) => {
 31 |   const value = (maxRgb / length) * (i + 3) * 2
 32 |   return `rgb(${value / 2}, 0, ${value})`
 33 | }
 34 | 
 35 | const indexToOrange = (i: number) => {
 36 |   const value = (maxRgb / length) * (i + 3) * 2
 37 |   return `rgb(${value}, ${value / 2}, 0)`
 38 | }
 39 | 
 40 | const indexToBlue = (i: number) => {
 41 |   const value = (maxRgb / length) * (i + 3) * 2
 42 |   return `rgb(0, ${value / 2}, ${value})`
 43 | }
 44 | 
 45 | const Slot = () => <div className={styles.slot} />
 46 | 
 47 | const reducer = (state: State, action: Action) => {
 48 |   switch (action.type) {
 49 |     case 'drop':
 50 |       let replaceId: any = -1
 51 |       let replace: any = undefined
 52 |       let moveId = state.stacks.findIndex(stack => stack.id === action.stackId)
 53 |       let move: any = undefined
 54 | 
 55 |       state.stacks.forEach((stack, id) => {
 56 |         if (stack.cards.findIndex(card => card.id === action.cardId) !== -1) {
 57 |           const [stays, moves] = split(
 58 |             card => card.id === action.cardId,
 59 |             stack.cards
 60 |           )
 61 | 
 62 |           move = moves
 63 |           replace = stays
 64 |           replaceId = id
 65 |         }
 66 |       })
 67 | 
 68 |       state.stacks[replaceId].cards = replace
 69 |       state.stacks[moveId].cards = [...state.stacks[moveId].cards, ...move]
 70 | 
 71 |       return { ...state }
 72 |     default:
 73 |       throw new Error(`Unrecognized action type, ${oneOf(friends)}`)
 74 |   }
 75 | }
 76 | 
 77 | const colors = [...Array(length)].map((_, index) => index)
 78 | 
 79 | let id = 0
 80 | const makeCard = (color: string) => {
 81 |   id = id + 1
 82 |   return { id: `${id}`, color }
 83 | }
 84 | 
 85 | const initial: State = {
 86 |   stacks: [
 87 |     {
 88 |       id: '1',
 89 |       cards: [...colors.map(indexToPink).slice(0, 5)].map(makeCard),
 90 |     },
 91 |     {
 92 |       id: '2',
 93 |       cards: [...colors.map(indexToOrange).slice(0, 4)].map(makeCard),
 94 |     },
 95 |     {
 96 |       id: '3',
 97 |       cards: [...colors.map(indexToBlue).slice(0, 3)].map(makeCard),
 98 |     },
 99 |   ],
100 | }
101 | 
102 | export default () => {
103 |   // It's important to use spread here so the context will be recreated on each
104 |   // render. That way there is no need to change droppables, since every change
105 |   // to them will happen only during rerender reaching *this* code.
106 |   const droppables: Array<{ stackId: string } & Dimensions> = [
107 |     ...defaultContext,
108 |   ]
109 | 
110 |   const [state, dispatch] = useReducer(reducer, { ...initial })
111 | 
112 |   const handleDrop = (stackId: ID, cardId: ID) =>
113 |     dispatch({ type: 'drop', stackId, cardId })
114 | 
115 |   return (
116 |     <div className={styles.app}>
117 |       <DragContext.Provider value={droppables}>
118 |         {state.stacks.map((stack, index) => (
119 |           <div key={index} className={styles.stack} tabIndex={-1}>
120 |             <Slot />
121 |             <Stack
122 |               id={stack.id}
123 |               cards={stack.cards}
124 |               onDrop={handleDrop}
125 |               render={(card: Card) => <Box color={card.color} />}
126 |               elementHeight={178}
127 |               verticalOffset={33}
128 |             />
129 |           </div>
130 |         ))}
131 |       </DragContext.Provider>
132 |     </div>
133 |   )
134 | }
135 | 


--------------------------------------------------------------------------------
/src/Drag.tsx:
--------------------------------------------------------------------------------
  1 | import React, {
  2 |   ReactNode,
  3 |   useContext,
  4 |   useRef,
  5 |   useEffect,
  6 |   MouseEvent,
  7 | } from 'react'
  8 | import DragContext from './DragContext'
  9 | import { ID, DropCallback } from './types'
 10 | import { ANIMATION_TIME, insideOneOf, translate, animate } from './utils'
 11 | 
 12 | type Props = {
 13 |   cardId: ID
 14 |   children: ReactNode
 15 |   onDrop: DropCallback
 16 |   elementHeight: number
 17 |   verticalOffset: number
 18 | }
 19 | 
 20 | const Drag = ({
 21 |   children,
 22 |   cardId,
 23 |   onDrop,
 24 |   elementHeight,
 25 |   verticalOffset,
 26 | }: Props) => {
 27 |   const draggable = useContext(DragContext)
 28 |   const ref = useRef<HTMLDivElement>(null)
 29 |   const offsetFromBottom = elementHeight - verticalOffset
 30 | 
 31 |   useEffect(() => {
 32 |     let pressed = false
 33 |     let pressPoint = { x: 0, y: -offsetFromBottom }
 34 |     let position = { x: 0, y: -offsetFromBottom }
 35 | 
 36 |     const callbacks = [
 37 |       {
 38 |         key: 'mousedown',
 39 |         fn: (event: MouseEvent<HTMLElement>) => {
 40 |           if ((event.target as HTMLElement).parentNode !== ref.current) {
 41 |             return
 42 |           }
 43 |           pressed = true
 44 |           ref.current!.style.cursor = 'grabbing'
 45 |           pressPoint = { x: event.pageX, y: event.pageY }
 46 |         },
 47 |       },
 48 |       {
 49 |         key: 'mouseup',
 50 |         fn: (event: MouseEvent<HTMLElement>) => {
 51 |           if (!pressed) return
 52 |           pressed = false
 53 |           const dropPoint = { x: event.pageX, y: event.pageY }
 54 |           const { left, top, height } = ref.current!.getBoundingClientRect()
 55 |           const isInside = insideOneOf(dropPoint, draggable)
 56 | 
 57 |           const animateBack = () => {
 58 |             ref.current!.animate(
 59 |               // @ts-ignore
 60 |               ...animate(position, { x: 0, y: -offsetFromBottom })
 61 |             )
 62 |             ref.current!.style.cursor = 'grab'
 63 |             ref.current!.style.transform = translate({
 64 |               x: 0,
 65 |               y: -offsetFromBottom,
 66 |             })
 67 |             pressPoint = { x: 0, y: -offsetFromBottom }
 68 |             position = { x: 0, y: -offsetFromBottom }
 69 |           }
 70 | 
 71 |           if (isInside) {
 72 |             const end = {
 73 |               x: position.x + isInside.left - left,
 74 |               y: position.y + isInside.top - top + verticalOffset,
 75 |             }
 76 | 
 77 |             // Hacky way to check if the drop target is the same stack it was
 78 |             // in or not.
 79 |             if (!(end.x === 0 && end.y < 0 && end.y > -elementHeight)) {
 80 |               ref.current!.animate(
 81 |                 // @ts-ignore
 82 |                 ...animate(position, end, { fill: 'forwards' })
 83 |               )
 84 |               setTimeout(() => onDrop(isInside.stackId, cardId), ANIMATION_TIME)
 85 |             } else {
 86 |               animateBack()
 87 |             }
 88 |           } else {
 89 |             animateBack()
 90 |           }
 91 |         },
 92 |       },
 93 |       {
 94 |         key: 'mousemove',
 95 |         fn: (event: MouseEvent<HTMLElement>) => {
 96 |           if (!pressed) return
 97 |           position = {
 98 |             x: event.pageX - pressPoint.x,
 99 |             y: event.pageY - pressPoint.y - offsetFromBottom,
100 |           }
101 |           ref.current!.style.transform = translate(position)
102 |         },
103 |       },
104 |     ]
105 | 
106 |     callbacks.forEach(callback => {
107 |       // @ts-ignore
108 |       window.addEventListener(callback.key, callback.fn)
109 |     })
110 |     return () => {
111 |       callbacks.forEach(callback => {
112 |         // @ts-ignore
113 |         window.removeEventListener(callback.key, callback.fn)
114 |       })
115 |     }
116 |   }, [draggable, cardId, onDrop])
117 | 
118 |   return (
119 |     <div
120 |       style={{
121 |         cursor: 'grab',
122 |         transform: `translate(0, -${offsetFromBottom}px)`,
123 |       }}
124 |       ref={ref}
125 |     >
126 |       {children}
127 |     </div>
128 |   )
129 | }
130 | 
131 | export default Drag
132 | 


--------------------------------------------------------------------------------
/src/DragContext.ts:
--------------------------------------------------------------------------------
 1 | import { createContext } from 'react'
 2 | import { ID, Dimensions } from './types'
 3 | 
 4 | export const defaultContext: any = []
 5 | 
 6 | const DragContext = createContext<Array<{ stackId: ID } & Dimensions>>(
 7 |   defaultContext
 8 | )
 9 | 
10 | export default DragContext
11 | 


--------------------------------------------------------------------------------
/src/Drop.tsx:
--------------------------------------------------------------------------------
 1 | import React, { useContext, useRef, useEffect } from 'react'
 2 | import DragContext from './DragContext'
 3 | import { ID } from './types'
 4 | import styles from './styles.module.css'
 5 | 
 6 | type Props = {
 7 |   stackId: ID
 8 | }
 9 | 
10 | const Drop = ({ stackId }: Props) => {
11 |   const draggable = useContext(DragContext)
12 |   const ref = useRef<HTMLDivElement>(null)
13 | 
14 |   useEffect(() => {
15 |     const { left, top, width, height } = ref.current!.getBoundingClientRect()
16 |     draggable.push({ stackId, left, top, width, height })
17 |   })
18 | 
19 |   return <div className={styles.drop} ref={ref} />
20 | }
21 | 
22 | export default Drop
23 | 


--------------------------------------------------------------------------------
/src/Stack.tsx:
--------------------------------------------------------------------------------
 1 | import React, { ReactNode } from 'react'
 2 | import { ID, Card, DropCallback } from './types'
 3 | import Drag from './Drag'
 4 | import Drop from './Drop'
 5 | 
 6 | type Props = {
 7 |   id: ID
 8 |   cards: Array<Card>
 9 |   onDrop: DropCallback
10 |   render: (card: Card) => ReactNode
11 |   verticalOffset: number
12 |   elementHeight: number
13 | }
14 | 
15 | const Stack = ({
16 |   id,
17 |   cards,
18 |   onDrop,
19 |   render,
20 |   elementHeight,
21 |   verticalOffset,
22 | }: Props) => {
23 |   if (cards.length === 0) return <Drop stackId={id} />
24 |   const [card, ...rest] = cards
25 |   return (
26 |     <Drag
27 |       cardId={card.id}
28 |       onDrop={onDrop}
29 |       elementHeight={elementHeight}
30 |       verticalOffset={verticalOffset}
31 |     >
32 |       {render(card)}
33 |       <Stack
34 |         id={id}
35 |         cards={rest}
36 |         onDrop={onDrop}
37 |         render={render}
38 |         elementHeight={elementHeight}
39 |         verticalOffset={verticalOffset}
40 |       />
41 |     </Drag>
42 |   )
43 | }
44 | 
45 | export default Stack
46 | 


--------------------------------------------------------------------------------
/src/index.css:
--------------------------------------------------------------------------------
 1 | @import url('https://rsms.me/inter/inter.css');
 2 | 
 3 | body {
 4 |   margin: 0;
 5 |   padding: 0;
 6 |   font-family: 'Inter', sans-serif;
 7 |   -webkit-font-smoothing: antialiased;
 8 |   -moz-osx-font-smoothing: grayscale;
 9 |   font-size: 16px;
10 |   letter-spacing: -0.011em;
11 |   line-height: 22px;
12 | }
13 | 
14 | @supports (font-variation-settings: normal) {
15 |   body {
16 |     font-family: 'Inter var', sans-serif;
17 |   }
18 | }
19 | 
20 | h2 {
21 |   font-size: 30px;
22 |   font-weight: 400;
23 |   letter-spacing: -0.021em;
24 |   line-height: 42px;
25 |   margin: 0;
26 | }
27 | 
28 | p {
29 |   margin: 0;
30 |   color: #777;
31 | }
32 | 
33 | * {
34 |   box-sizing: border-box;
35 | }
36 | 


--------------------------------------------------------------------------------
/src/index.tsx:
--------------------------------------------------------------------------------
1 | import React from 'react'
2 | import ReactDOM from 'react-dom'
3 | import './index.css'
4 | import App from './App'
5 | 
6 | ReactDOM.render(<App />, document.getElementById('root'))
7 | 


--------------------------------------------------------------------------------
/src/react-app-env.d.ts:
--------------------------------------------------------------------------------
1 | /// <reference types="react-scripts" />
2 | 


--------------------------------------------------------------------------------
/src/styles.module.css:
--------------------------------------------------------------------------------
 1 | .app {
 2 |   position: relative;
 3 |   display: flex;
 4 |   justify-content: center;
 5 |   padding-top: 100px;
 6 | }
 7 | 
 8 | .box {
 9 |   width: 114px;
10 |   height: 178px;
11 |   border-radius: 8px;
12 |   /* box-shadow: 0 0 0 1px #000 inset; */
13 | }
14 | 
15 | .drop {
16 |   width: 114px;
17 |   height: 178px;
18 |   margin-top: -178px;
19 |   border-radius: 8px;
20 | }
21 | 
22 | div:focus {
23 |   z-index: 10;
24 |   outline: 0;
25 | }
26 | 
27 | .stack {
28 |   margin-right: 50px;
29 | }
30 | 
31 | .stack:last-child {
32 |   margin-right: 0;
33 | }
34 | 
35 | .slot {
36 |   /* background-color: rgba(0, 0, 0, 0.3); */
37 |   left: 0px;
38 |   top: 0px;
39 |   width: 114px;
40 |   height: 178px;
41 |   cursor: default;
42 |   border-radius: 8px;
43 | }
44 | 


--------------------------------------------------------------------------------
/src/types.ts:
--------------------------------------------------------------------------------
 1 | export type ID = string
 2 | 
 3 | export type DropCallback = (stackId: ID, cardId: ID) => void
 4 | 
 5 | export type Dimensions = {
 6 |   left: number
 7 |   top: number
 8 |   width: number
 9 |   height: number
10 | }
11 | 
12 | export type Point = {
13 |   x: number
14 |   y: number
15 | }
16 | 
17 | export type Card = {
18 |   id: string
19 |   color: string
20 | }
21 | 


--------------------------------------------------------------------------------
/src/utils.ts:
--------------------------------------------------------------------------------
 1 | import { ID, Point, Dimensions } from './types'
 2 | 
 3 | export const ANIMATION_TIME = 250
 4 | 
 5 | export const translate = (p: Point) => `translate(${p.x}px, ${p.y}px)`
 6 | 
 7 | export const inside = (p: Point, d: Dimensions) =>
 8 |   p.x >= d.left &&
 9 |   p.x <= d.left + d.width &&
10 |   p.y >= d.top &&
11 |   p.y <= d.top + d.height
12 | 
13 | export const insideOneOf = (
14 |   p: Point,
15 |   array: Array<{ stackId: ID } & Dimensions>
16 | ) => {
17 |   for (let i = 0; i < array.length; i++) {
18 |     if (inside(p, array[i])) return array[i]
19 |   }
20 | }
21 | 
22 | export const animate = (from: Point, to: Point, options: any) => [
23 |   [{ transform: translate(from) }, { transform: translate(to) }],
24 |   {
25 |     duration: ANIMATION_TIME,
26 |     easing: 'cubic-bezier(0.2, 1, 0.1, 1)',
27 |     ...options,
28 |   },
29 | ]
30 | 
31 | export const oneOf = (array: Array<any>) =>
32 |   array[Math.round(Math.random() * (array.length - 1))]
33 | 
34 | export const friends = ['bro', 'pal', 'mate', 'fella', 'buddy', 'dude']
35 | 
36 | export const split = function<T>(
37 |   predicate: (element: T) => boolean,
38 |   array: Array<T>
39 | ) {
40 |   const index = array.findIndex(predicate, array)
41 |   if (index === -1) {
42 |     throw new Error(`Not present in ${array}`)
43 |   }
44 |   return [array.slice(0, index), array.slice(index)]
45 | }
46 | 


--------------------------------------------------------------------------------
/tsconfig.json:
--------------------------------------------------------------------------------
 1 | {
 2 |   "compilerOptions": {
 3 |     "target": "es5",
 4 |     "lib": [
 5 |       "dom",
 6 |       "dom.iterable",
 7 |       "esnext"
 8 |     ],
 9 |     "allowJs": true,
10 |     "skipLibCheck": true,
11 |     "esModuleInterop": true,
12 |     "allowSyntheticDefaultImports": true,
13 |     "strict": true,
14 |     "forceConsistentCasingInFileNames": true,
15 |     "module": "esnext",
16 |     "moduleResolution": "node",
17 |     "resolveJsonModule": true,
18 |     "isolatedModules": true,
19 |     "noEmit": true,
20 |     "jsx": "preserve"
21 |   },
22 |   "include": [
23 |     "src"
24 |   ]
25 | }
26 | 


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