import React, { useEffect, useState, useRef, useMemo, useCallback } from 'react';
import { Text, Editor, createEditor, Node, Range, Point, Transforms } from 'slate';
import {
Slate,
Editable,
withReact,
useSelected,
useFocused,
useSlate } from 'slate-react';
import { withHistory } from 'slate-history';
import { cx, css } from 'emotion';
import { jsx } from 'slate-hyperscript';
import isHotkey from 'is-hotkey';
import imageExtensions from 'image-extensions';
import isUrl from 'is-url';
import {
MdCode,
MdFormatBold,
MdFormatItalic,
MdFormatListBulleted,
MdFormatListNumbered, MdFormatQuote, MdFormatUnderlined, MdImage, MdList,
MdLooksOne, MdLooksTwo, MdLooks3
} from 'react-icons/md';
const HOTKEYS = {
'mod+b': 'bold',
'mod+i': 'italic',
'mod+u': 'underline',
'mod+`': 'code',
};
const LIST_TYPES = ['numbered-list', 'bulleted-list'];
const ELEMENT_TAGS = {
A: el => ({ type: 'link', url: el.getAttribute('href') }),
BLOCKQUOTE: () => ({ type: 'quote' }),
H1: () => ({ type: 'heading-one' }),
H2: () => ({ type: 'heading-two' }),
H3: () => ({ type: 'heading-three' }),
H4: () => ({ type: 'heading-four' }),
H5: () => ({ type: 'heading-five' }),
H6: () => ({ type: 'heading-six' }),
IMG: el => ({ type: 'image', url: el.getAttribute('src') }),
LI: () => ({ type: 'list-item' }),
OL: () => ({ type: 'numbered-list' }),
P: () => ({ type: 'paragraph' }),
PRE: () => ({ type: 'code' }),
UL: () => ({ type: 'bulleted-list' }),
TABLE: () => ({ type: 'table' }),
TBODY: () => ({ type: 'tbody' }),
THEAD: () => ({ type: 'thead' }),
TR: () => ({ type: 'table-row' }),
TD: () => ({ type: 'table-cell' }),
TH: () => ({ type: 'table-cell-header' }),
HEADER: () => ({ type: 'header' }),
SECTION: () => ({ type: 'section' }),
}
// COMPAT: `B` is omitted here because Google Docs uses `<b>` in weird ways.
const TEXT_TAGS = {
CODE: () => ({ code: true }),
DEL: () => ({ strikethrough: true }),
EM: () => ({ italic: true }),
I: () => ({ italic: true }),
S: () => ({ strikethrough: true }),
STRONG: () => ({ bold: true }),
U: () => ({ underline: true }),
}
export const deserialize = (el, mAttrs = {}) => {
console.log('deserialize:', el, el.nodeType, el.nodeName)
if (el.nodeType === 3) {
return el.textContent
} else if (el.nodeType !== 1) {
return null
} else if (el.nodeName === 'BR') {
return '\n'
}
const { nodeName } = el
let parent = el
if (el.childNodes[0]) {
console.log('deserialize:sub', el.childNodes[0], el.childNodes[0].nodeName)
}
let children = [];
if (nodeName === 'PRE') {
if (el.childNodes[0] && el.childNodes[0].nodeName === 'CODE') {
parent = el.childNodes[0]
}
console.log('deserialize:pre:', parent, parent.childNodes);
children = Array.from(parent.childNodes)
.map((e) => {
return {
text: e.textContent,
code: true,
}
})
} else {
children = Array.from(parent.childNodes)
.map(deserialize)
.flat()
}
if (el.nodeName === 'BODY') {
return jsx('fragment', {}, children);
}
if (ELEMENT_TAGS[nodeName]) {
const attrs = ELEMENT_TAGS[nodeName](el);
return jsx('element', attrs, children)
}
if (TEXT_TAGS[nodeName]) {
const attrs = TEXT_TAGS[nodeName](el);
return children.map(child => jsx('text', attrs, child))
}
return children
}
export default function RichEditor(props) {
const renderElement = useCallback(props => <Element {...props} />, [])
const renderLeaf = useCallback(props => <Leaf {...props} />, [])
const editor = useMemo(
() => withImages(withTables(withHtml(withReact(withHistory(createEditor()))))),
[]
)
let fileUploadRef = useRef(null)
let onChangeUpload = (e) => {
fnRemoteImage(editor, e.target.files)
}
useEffect(()=> {
props.editorRef(editor)
, []});
return (
<Slate editor={editor}
value={props.value}
onChange={newValue => props.onChange(newValue)}>
<Toolbar>
<MarkButton format="bold" icon="format_bold" />
<MarkButton format="italic" icon="format_italic" />
<MarkButton format="underline" icon="format_underlined" />
<MarkButton format="code" icon="code" />
<BlockButton format="heading-one" icon="heading-one" />
<BlockButton format="heading-two" icon="heading-two" />
<BlockButton format="heading-three" icon="heading-three" />
<BlockButton format="block-quote" icon="format_quote" />
<BlockButton format="numbered-list" icon="format_list_numbered" />
<BlockButton format="bulleted-list" icon="format_list_bulleted" />
<Button
onMouseDown={event => {
event.preventDefault()
fileUploadRef.current.click()
}}
>
<MdImage size="24" />
</Button>
<input type="file" onChange={onChangeUpload} id="chooseFile" className="invisible" ref={fileUploadRef} />
</Toolbar>
<Editable
className="slate-editor"
renderElement={renderElement}
renderLeaf={renderLeaf}
spellCheck
autoFocus
onKeyDown={event => {
for (const hotkey in HOTKEYS) {
if (isHotkey(hotkey, event)) {
event.preventDefault()
const mark = HOTKEYS[hotkey]
toggleMark(editor, mark)
}
}
}}
/>
</Slate>
)
};
const fnRemoteImage = (editor, files) => {
for (const file of files) {
const [mime] = file.type.split('/');
if (mime === 'image') {
const formData = new FormData();
formData.append("image", file);
fetch("/api/note/upload", {
method: "POST",
body: formData
}
)
.then(response => response.json())
.then(result => {
console.log(result);
insertImage(editor, result.data.uri)
})
.catch(error => {
alert("Error:", error);
});
}
}
}
const withImages = editor => {
const { insertData, isVoid } = editor
editor.isVoid = element => {
return element.type === 'image' ? true : isVoid(element)
}
editor.insertData = data => {
const text = data.getData('text/plain')
const { files } = data
console.log('insertData:', files)
if (files && files.length > 0) {
fnRemoteImage(editor, files)
} else if (isImageUrl(text)) {
insertImage(editor, text)
} else {
insertData(data)
}
}
return editor
}
const isImageUrl = url => {
if (!url) return false
if (!isUrl(url)) return false
const ext = new URL(url).pathname.split('.').pop()
return imageExtensions.includes(ext)
}
const insertImage = (editor, url) => {
const text = { text: '' }
const image = { type: 'image', url, children: [text] }
Transforms.insertNodes(editor, image)
}
const withTables = editor => {
const { deleteBackward, deleteForward, insertBreak } = editor
editor.deleteBackward = unit => {
const { selection } = editor
if (selection && Range.isCollapsed(selection)) {
const [cell] = Editor.nodes(editor, {
match: n => n.type === 'table-cell',
})
if (cell) {
const [, cellPath] = cell
const start = Editor.start(editor, cellPath)
if (Point.equals(selection.anchor, start)) {
return
}
}
}
deleteBackward(unit)
}
editor.deleteForward = unit => {
const { selection } = editor
if (selection && Range.isCollapsed(selection)) {
const [cell] = Editor.nodes(editor, {
match: n => n.type === 'table-cell',
})
if (cell) {
const [, cellPath] = cell
const end = Editor.end(editor, cellPath)
if (Point.equals(selection.anchor, end)) {
return
}
}
}
deleteForward(unit)
}
editor.insertBreak = () => {
const { selection } = editor
if (selection) {
const [table] = Editor.nodes(editor, { match: n => n.type === 'table' })
if (table) {
return
}
}
insertBreak()
}
return editor
}
const withHtml = editor => {
const { insertData, isInline, isVoid } = editor
editor.isInline = element => {
return element.type === 'link' ? true : isInline(element)
}
editor.isVoid = element => {
return element.type === 'image' ? true : isVoid(element)
}
editor.insertData = data => {
const html = data.getData('text/html')
if (html) {
const parsed = new DOMParser().parseFromString(html, 'text/html')
const fragment = deserialize(parsed.body)
Transforms.insertFragment(editor, fragment)
return
}
insertData(data)
}
return editor
}
const Element = props => {
const { attributes, children, element } = props
switch (element.type) {
case 'thead':
return (
<thead {...attributes}>{children}</thead>
)
case 'tbody':
return (
<tbody {...attributes}>{children}</tbody>
)
case 'table':
return (
<table {...attributes}>{children}</table>
)
case 'table-row':
return <tr {...attributes}>{children}</tr>
case 'table-cell':
return <td {...attributes}>{children}</td>
case 'table-cell-header':
return <th {...attributes}>{children}</th>
case 'header':
return <header {...attributes}>{children}</header>
case 'section':
return <section {...attributes}>{children}</section>
case 'block-quote':
return <blockquote {...attributes}>{children}</blockquote>
case 'code':
return (
<pre>
<code {...attributes}>{children}</code>
</pre>
)
case 'bulleted-list':
return <ul {...attributes}>{children}</ul>
case 'heading-one':
return <h1 {...attributes}>{children}</h1>
case 'heading-two':
return <h2 {...attributes}>{children}</h2>
case 'heading-three':
return <h3 {...attributes}>{children}</h3>
case 'heading-four':
return <h4 {...attributes}>{children}</h4>
case 'heading-five':
return <h5 {...attributes}>{children}</h5>
case 'heading-six':
return <h6 {...attributes}>{children}</h6>
case 'list-item':
return <li {...attributes}>{children}</li>
case 'numbered-list':
return <ol {...attributes}>{children}</ol>
case 'link':
return (
<a href={element.url} {...attributes}>
{children}
</a>
)
case 'image':
return <ImageElement {...props} />
default:
return <p {...attributes}>{children}</p>
}
}
const ImageElement = ({ attributes, children, element }) => {
const selected = useSelected()
const focused = useFocused()
return (
<div {...attributes}>
{children}
<img
src={element.url}
className={css`
display: block;
max-width: 100%;
max-height: 20em;
box-shadow: ${selected && focused ? '0 0 0 2px blue;' : 'none'};
`}
/>
</div>
)
}
const Leaf = ({ attributes, children, leaf }) => {
if (leaf.bold) {
children = <strong>{children}</strong>
}
if (leaf.code) {
children = <code>{children}</code>
}
if (leaf.italic) {
children = <em>{children}</em>
}
if (leaf.underline) {
children = <u>{children}</u>
}
if (leaf.strikethrough) {
children = <del>{children}</del>
}
return <span {...attributes}>{children}</span>
}
const BlockButton = ({ format, icon }) => {
const editor = useSlate();
let iconCompo = null;
switch (icon) {
case 'heading-one':
iconCompo = (<MdLooksOne size={24} />);
break;
case 'heading-two':
iconCompo = (<MdLooksTwo size={24} />);
break;
case 'heading-three':
iconCompo = (<MdLooks3 size={24} />);
break;
case 'format_quote':
iconCompo = (<MdFormatQuote size={24} />);
break;
case 'format_list_numbered':
iconCompo = (<MdFormatListNumbered size={24} />);
break;
case 'format_list_bulleted':
iconCompo = (<MdFormatListBulleted size={24} />);
break;
}
return (
<Button
active={isBlockActive(editor, format)}
onMouseDown={event => {
event.preventDefault()
toggleBlock(editor, format)
}}
>
{iconCompo}
</Button>
)
}
const MarkButton = ({ format, icon }) => {
const editor = useSlate();
let iconCompo = null;
switch (icon) {
case 'format_bold':
iconCompo = (<MdFormatBold size={24} />);
break;
case 'format_italic':
iconCompo = (<MdFormatItalic size={24} />);
break;
case 'format_underlined':
iconCompo = (<MdFormatUnderlined size={24} />);
break;
case 'code':
iconCompo = (<MdCode size={24} />);
break;
}
return (
<Button
active={isMarkActive(editor, format)}
onMouseDown={event => {
event.preventDefault()
toggleMark(editor, format)
}}
>
{iconCompo}
</Button>
)
}
const toggleBlock = (editor, format) => {
const isActive = isBlockActive(editor, format)
const isList = LIST_TYPES.includes(format)
Transforms.unwrapNodes(editor, {
match: n => LIST_TYPES.includes(n.type),
split: true,
})
Transforms.setNodes(editor, {
type: isActive ? 'paragraph' : isList ? 'list-item' : format,
})
if (!isActive && isList) {
const block = { type: format, children: [] }
Transforms.wrapNodes(editor, block)
}
}
const toggleMark = (editor, format) => {
const isActive = isMarkActive(editor, format)
if (isActive) {
Editor.removeMark(editor, format)
} else {
Editor.addMark(editor, format, true)
}
}
const isBlockActive = (editor, format) => {
const [match] = Editor.nodes(editor, {
match: n => n.type === format,
})
return !!match
}
const isMarkActive = (editor, format) => {
const marks = Editor.marks(editor)
return marks ? marks[format] === true : false
}
export const Menu = React.forwardRef(
(
{ className, ...props },
ref
) => (
<div
{...props}
ref={ref}
className={cx(
className,
css`
& > * {
display: inline-block;
}
& > * + * {
margin-left: 15px;
}
`
)}
/>
)
)
export const Toolbar = React.forwardRef(
(
{ className, ...props },
ref
) => (
<Menu
{...props}
ref={ref}
className={cx(
className,
css`
position: relative;
padding: 1px 11px 8px;
border-bottom: 2px solid #eee;
`
)}
/>
)
)
export const Button = React.forwardRef(
(
{
className,
active,
reversed,
...props
},
ref
) => (
<span
{...props}
ref={ref}
className={cx(
className,
css`
cursor: pointer;
color: ${reversed
? active
? 'white'
: '#aaa'
: active
? 'black'
: '#ccc'};
`
)}
/>
)
)
export const Icon = React.forwardRef(
(
{ className, ...props },
ref
) => (
<span
{...props}
ref={ref}
className={cx(
'material-icons',
className,
css`
font-size: 18px;
vertical-align: text-bottom;
`
)}
/>
)
)
Write, Run & Share Javascript code online using OneCompiler's JS online compiler for free. It's one of the robust, feature-rich online compilers for Javascript language. Getting started with the OneCompiler's Javascript editor is easy and fast. The editor shows sample boilerplate code when you choose language as Javascript and start coding.
Javascript(JS) is a object-oriented programming language which adhere to ECMA Script Standards. Javascript is required to design the behaviour of the web pages.
var readline = require('readline');
var rl = readline.createInterface({
input: process.stdin,
output: process.stdout,
terminal: false
});
rl.on('line', function(line){
console.log("Hello, " + line);
});
| Keyword | Description | Scope |
|---|---|---|
| var | Var is used to declare variables(old way of declaring variables) | Function or global scope |
| let | let is also used to declare variables(new way) | Global or block Scope |
| const | const is used to declare const values. Once the value is assigned, it can not be modified | Global or block Scope |
let greetings = `Hello ${name}`
const msg = `
hello
world!
`
An array is a collection of items or values.
let arrayName = [value1, value2,..etc];
// or
let arrayName = new Array("value1","value2",..etc);
let mobiles = ["iPhone", "Samsung", "Pixel"];
// accessing an array
console.log(mobiles[0]);
// changing an array element
mobiles[3] = "Nokia";
Arrow Functions helps developers to write code in concise way, it’s introduced in ES6.
Arrow functions can be written in multiple ways. Below are couple of ways to use arrow function but it can be written in many other ways as well.
() => expression
const numbers = [0, 1, 2, 3, 4, 5, 6, 7, 8, 9]
const squaresOfEvenNumbers = numbers.filter(ele => ele % 2 == 0)
.map(ele => ele ** 2);
console.log(squaresOfEvenNumbers);
let [firstName, lastName] = ['Foo', 'Bar']
let {firstName, lastName} = {
firstName: 'Foo',
lastName: 'Bar'
}
const {
title,
firstName,
lastName,
...rest
} = record;
//Object spread
const post = {
...options,
type: "new"
}
//array spread
const users = [
...adminUsers,
...normalUsers
]
function greetings({ name = 'Foo' } = {}) { //Defaulting name to Foo
console.log(`Hello ${name}!`);
}
greet() // Hello Foo
greet({ name: 'Bar' }) // Hi Bar
IF is used to execute a block of code based on a condition.
if(condition){
// code
}
Else part is used to execute the block of code when the condition fails.
if(condition){
// code
} else {
// code
}
Switch is used to replace nested If-Else statements.
switch(condition){
case 'value1' :
//code
[break;]
case 'value2' :
//code
[break;]
.......
default :
//code
[break;]
}
For loop is used to iterate a set of statements based on a condition.
for(Initialization; Condition; Increment/decrement){
//code
}
While is also used to iterate a set of statements based on a condition. Usually while is preferred when number of iterations are not known in advance.
while (condition) {
// code
}
Do-while is also used to iterate a set of statements based on a condition. It is mostly used when you need to execute the statements atleast once.
do {
// code
} while (condition);
ES6 introduced classes along with OOPS concepts in JS. Class is similar to a function which you can think like kind of template which will get called when ever you initialize class.
class className {
constructor() { ... } //Mandatory Class method
method1() { ... }
method2() { ... }
...
}
class Mobile {
constructor(model) {
this.name = model;
}
}
mbl = new Mobile("iPhone");