TypeScript functions to convert from Base64 to UTF8 and vice versa | José Quinto

Introduction

Few days ago I wrote a post about uploading JSON object using JavaScript. There are some dependencies using this approach, which are b64EncodeUnicode and b64DecodeUnicode functions.

I’d like to share how to write these functions using TypeScript:

	/*
	* Function to convert from UTF8 to Base64 solving the Unicode Problem
	* Requires: window.btoa and window.encodeURIComponent functions
	* More info: http://stackoverflow.com/questions/30106476/using-javascripts-atob-to-decode-base64-doesnt-properly-decode-utf-8-strings
	* Samples:
	* b64EncodeUnicode('✓ à la mode'); // "4pyTIMOgIGxhIG1vZGU="
	* b64EncodeUnicode('\n'); // "Cg=="
	*/
	public static b64EncodeUnicode(str: string): string {
	if (window
	&& "btoa" in window
	&& "encodeURIComponent" in window) {
	return btoa(encodeURIComponent(str).replace(/%([0-9A-F]{2})/g, (match, p1) => {
	return String.fromCharCode(("0x" + p1) as any);
	}));
	} else {
	console.warn("b64EncodeUnicode requirements: window.btoa and window.encodeURIComponent functions");
	return null;
	}
	}
	/*
	* Function to convert from Base64 to UTF8 solving the Unicode Problem
	* Requires window.atob and window.decodeURIComponent functions
	* More info: http://stackoverflow.com/questions/30106476/using-javascripts-atob-to-decode-base64-doesnt-properly-decode-utf-8-strings
	* Samples:
	* b64DecodeUnicode('4pyTIMOgIGxhIG1vZGU='); // "✓ à la mode"
	* b64DecodeUnicode('Cg=='); // "\n"
	*/
	public static b64DecodeUnicode(str: string): string {
	if (window
	&& "atob" in window
	&& "decodeURIComponent" in window) {
	return decodeURIComponent(Array.prototype.map.call(atob(str), (c) => {
	return "%" + ("00" + c.charCodeAt(0).toString(16)).slice(-2);
	}).join(""));
	} else {
	console.warn("b64DecodeUnicode requirements: window.atob and window.decodeURIComponent functions");
	return null;
	}
	}
	// That is a specific funtion to upload the object to SharePoint (Office 365)
	public static JSONObjectToSPFileBinary(jsonObject: any): SP.Base64EncodedByteArray {
	// Convert JSON object to File
	// 1. Convert JSON object to string
	const jsonString = JSON.stringify(jsonObject, null, 0);
	// 2. Convert string to Base64 Encoded Byte Array
	const base64EncodedArray = Utils.b64EncodeUnicode(jsonString);
	// 3. Crate SP.Base64EncodedByteArray with the content
	return new SP.Base64EncodedByteArray(base64EncodedArray);
	// Reverse: b64DecodeUnicode(content.toBase64String())
	// End Convert JSON object to File
	}

view raw JQ.TypeScript.ConvertBase64toUTF.ts hosted with ❤ by GitHub