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joplin notion extension/Web Development/Javascript/file split and merge.md

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+file split and merge
+
+FrontEnd
+```html
+<!DOCTYPE html>
+<html lang="en">
+<head>
+	<meta charset="UTF-8">
+	<meta name="viewport" content="width=device-width, initial-scale=1.0">
+	<title>Document</title>
+</head>
+<body>
+	<input id="fileInput" type="file" name="" id=""><br>
+	<button onclick="submit()" id="submit">Submit</button>
+	<script src="script.js"></script>
+</body>
+</html>
+```
+&nbsp;
+```js
+const fileEle=document.querySelector("#fileInput")
+const sliceSize=10*1024*1024 // 10MB
+
+const submit=()=>{
+	const file= fileEle.files[0]
+	const fileSize=file.size
+
+	let start=0;
+	let end=sliceSize
+
+	const filePieces=[]
+	while(end<=fileSize)
+	{
+		const chunk = file.slice(start,end)
+		filePieces.push(chunk)
+		start=end
+		end+=sliceSize	
+	}
+
+	if(start<fileSize)
+	{
+		const chunk = file.slice(start,fileSize)
+		filePieces.push(chunk)
+	}
+
+	console.log('file: ',file)
+	console.log('filePieces: ',filePieces)
+
+	const blob=new Blob(filePieces)
+	const a=document.createElement("a")
+	const link=URL.createObjectURL(blob)
+	a.href=	link
+	a.download="something1"
+	a.click()
+
+
+```