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Commit a83168c

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chore: Merge pull request #756 from nibble-4bits/algorithm/bufferToBase64
Create algorithm for converting binary data to base64
2 parents fc0647e + 5d56140 commit a83168c

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‎Conversions/ArrayBufferToBase64.js‎

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// About base64: https://en.wikipedia.org/wiki/Base64
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/**
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* Converts an array of bytes to base64 encoding
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* @param {ArrayBuffer} binaryData An ArrayBuffer which represents an array of bytes
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* @returns {string} A string containing the base64 encoding of `binaryData`
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*/
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function bufferToBase64 (binaryData) {
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// The base64 encoding uses the following set of characters to encode any binary data as text
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const base64Table = 'ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/'
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// Every 3 bytes translates to 4 base64 characters, if we have less than 3 bytes we must append '=' chars as padding
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const padding = 3 - (binaryData.byteLength % 3)
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// Create an instance of Uint8Array, to read from the binaryData array buffer
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const byteView = new Uint8Array(binaryData)
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let result = ''
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// Loop through all bytes in the buffer, in increments of 3 bytes
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for (let i = 0; i < byteView.byteLength; i += 3) {
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// Get the index for the next 4 base64 chars
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const char1 = (byteView[i] & 252) >> 2
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const char2 = ((byteView[i] & 3) << 4) + ((byteView[i + 1] & 240) >> 4)
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const char3 = ((byteView[i + 1] & 15) << 2) + ((byteView[i + 2] & 192) >> 6)
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const char4 = byteView[i + 2] & 63
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result +=
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base64Table[char1] +
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base64Table[char2] +
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base64Table[char3] +
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base64Table[char4]
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}
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// Add padding '=' chars if needed
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if (padding !== 3) {
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const paddedResult = result.slice(0, result.length - padding) + '='.repeat(padding)
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return paddedResult
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}
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return result
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}
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export { bufferToBase64 }
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import { bufferToBase64 } from '../ArrayBufferToBase64'
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import { TextEncoder } from 'util'
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describe('ArrayBufferToBase64', () => {
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it('should encode "Hello, world!" as "SGVsbG8sIHdvcmxkIQ=="', () => {
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const testString = 'Hello, world!'
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const encoder = new TextEncoder()
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const helloWorldBuffer = encoder.encode(testString)
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const result = bufferToBase64(helloWorldBuffer)
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expect(result).toBe('SGVsbG8sIHdvcmxkIQ==')
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})
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it('should encode binary buffer [55,23,177,234,68,26,90] as "Nxex6kQaWg=="', () => {
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const testBuffer = new Uint8Array([55, 23, 177, 234, 68, 26, 90])
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const result = bufferToBase64(testBuffer)
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expect(result).toBe('Nxex6kQaWg==')
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})
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it('should encode binary buffer [0,1,2,3,4,5,6,7,8,9] as "AAECAwQFBgcICQ=="', () => {
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const testBuffer = new Uint8Array([0, 1, 2, 3, 4, 5, 6, 7, 8, 9])
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const result = bufferToBase64(testBuffer)
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expect(result).toBe('AAECAwQFBgcICQ==')
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})
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})

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