is-base64

Predicate that returns true if base64 string.

Install

npm install is-base64

Usage

var isBase64 = require('is-base64');
 
var string = 'iVBORw0KGgoAAAAN ... kSuQmCC';
var stringWithMime = 'data:image/png;base64,iVBORw0KGgoAAAA ... AAElFTkSuQmCC';
 
console.log(isBase64(string)); // true
console.log(isBase64(stringWithMime)); // false
console.log(isBase64(stringWithMime, {allowMime: true})); // true
console.log(isBase64(string, {mimeRequired: true})); // false
console.log(isBase64(stringWithMime, {mimeRequired: true})); // true
console.log(isBase64('1342234')); // false
console.log(isBase64('afQ$%rfew')); // false
console.log(isBase64('dfasdfr342')); // false
console.log(isBase64('uuLMhh==')); // true
console.log(isBase64('uuLMhh')); // false
console.log(isBase64('uuLMhh', {paddingRequired: false})); // true
console.log(isBase64('')); // true
console.log(isBase64('', {allowEmpty: false})); // false

API

isBase64(string, options)

• {string} string - string to check if is valid base64 string

• {object} [options]

  • [options.allowEmpty=true] {boolean} - returns true for empty string
  • [options.allowMime=false] {boolean} - returns true for valid strings with optional mime
  • [options.mimeRequired=false] {boolean} - returns true for valid strings with mime
  • [options.paddingRequired=true] {boolean} - returns true for valid strings with valid padding

CLI

Install CLI:

npm install -g is-base64

CLI example:

$ is-base64 aGVsbG8gd29ybGQ=
true

Piping example:

$ echo aGVsbG8gd29ybGQ= | is-base64
true

FAQ

• Q: Why is empty string "" a valid base64 string by default?

  • A: According to RFC 4648 Section 10, the following is valid test vector:

    BASE64("") = ""
    

License

MIT