Adds secret keys from local JSON files as Base64 to `now` secrets.

now-secrets-json.js

const fs = require('fs');

const GOOGLE_APPLICATION_CREDENTIALS = 'keys/google_application_credentials.json';

/**
 * Adds secret keys from local JSON files as Base64 to `now` secrets.
 * 
 * e.g. `node now-secrets-json.js'
 */
function main() {
  const encodedKey = btoa(fs.readFileSync(GOOGLE_APPLICATION_CREDENTIALS));
  const exec = require('child_process').exec;
  exec(`now secret add google_application_credentials_data ${encodedKey}`, function callback(error, stdout, stderr){
    if (error) {
      throw error;
    }

    console.log(stdout);
  });
}

main();

/**
 * Converts a string into Base64.
 *
 * @param {string} str
 * @returns {string}
 */
function btoa(str) {
  if (Buffer.byteLength(str) !== str.length)
    throw new Error('bad string!');
  return Buffer(str, 'binary').toString('base64');
}