@0xbigboss/react-native-passkeys
Version:
A library for using (webauthn) passkeys on iOS, Android & web with a single api
46 lines • 1.89 kB
JavaScript
// ! taken from https://github.com/MasterKale/SimpleWebAuthn/blob/e02dce6f2f83d8923f3a549f84e0b7b3d44fa3da/packages/browser/src/helpers/base64URLStringToBuffer.ts
/**
* Convert from a Base64URL-encoded string to an Array Buffer. Best used when converting a
* credential ID from a JSON string to an ArrayBuffer, like in allowCredentials or
* excludeCredentials
*
* Helper method to compliment `bufferToBase64URLString`
*/
export function base64URLStringToBuffer(base64URLString) {
// Convert from Base64URL to Base64
const base64 = base64URLString.replace(/-/g, '+').replace(/_/g, '/');
/**
* Pad with '=' until it's a multiple of four
* (4 - (85 % 4 = 1) = 3) % 4 = 3 padding
* (4 - (86 % 4 = 2) = 2) % 4 = 2 padding
* (4 - (87 % 4 = 3) = 1) % 4 = 1 padding
* (4 - (88 % 4 = 0) = 4) % 4 = 0 padding
*/
const padLength = (4 - (base64.length % 4)) % 4;
const padded = base64.padEnd(base64.length + padLength, '=');
// Convert to a binary string
const binary = atob(padded);
// Convert binary string to buffer
const buffer = new ArrayBuffer(binary.length);
const bytes = new Uint8Array(buffer);
for (let i = 0; i < binary.length; i++) {
bytes[i] = binary.charCodeAt(i);
}
return buffer;
}
/**
* Convert the given array buffer into a Base64URL-encoded string. Ideal for converting various
* credential response ArrayBuffers to string for sending back to the server as JSON.
*
* Helper method to compliment `base64URLStringToBuffer`
*/
export function bufferToBase64URLString(buffer) {
const bytes = new Uint8Array(buffer);
let str = '';
for (const charCode of bytes) {
str += String.fromCharCode(charCode);
}
const base64String = btoa(str);
return base64String.replace(/\+/g, '-').replace(/\//g, '_').replace(/=/g, '');
}
//# sourceMappingURL=base64.js.map