BERT

Binary ERlang Term serialization library for Javascript. (An updated version of this repo )

Usage

--------------------------------

$3

When needing to consume data in Javascript from an Erlang system, the Erlang
system can simply send encoded binary data:

Elixir/Erlang:
``elixir


This is Elixir code, but function calls will be very similar in Erlang

personData = %{
name: "Bob",
age: 32,
eye_color: "Brown",
personality_traits: [
"Funny",
"Inquisitive"
]
}

Convert to binary

:erlang.term_to_binary(personData)

.... Code that sends binary data to javascript

`

Javascript:
`javascript
// ... Code that receives binary data from erlang/elixir and stores it
// to a variable, personData

const Bert = require('bert-elixir')

const decodedPerson = Bert.decode(personData)
/*
=> { age: 32,
eye_color: 'Brown',
name: 'Bob',
personality_traits: [ 'Funny', 'Inquisitive' ]
}
*/
`

Modifying this data and sending it back to Erlang/Elixir would be as simple as:

Javascript:
`javascript
// ... Assuming we have a decodedPerson object

decodedPerson.age = 38
decodedPerson.name = 'Robert'

const reEncodedPerson = Bert.encode(decodedPerson)

// ... Send the binary
`

Elixir/Erlang:
`elixir


... After having received binary data and setting it to variable modifiedPersonData:

decodedPerson = :erlang.binary_to_term(modifiedPersonData, [:safe])

=> %{ age: 38, eye_color: "Brown", name: "Robert", personality_traits: ["Funny", "Inquisitive"] }


`

safe option should be always used when decoding an untrusted input, make also sure to have already all required atoms in the atoms table.

$3

#### Maps (Elixir)

Javascript objects map directly to Maps in Erlang

`javascript
const Bert = require('bert-elixir')

// To encode a javascript object to an elixir map:
const mapToEncode = { a: 1, b: "hello!", c: [1, 2, 3] }
const encodedMap = Bert.encode(mapToEncode)

// BinaryToList shows individual bytes as a javascript array
console.log(Bert.binaryToList(encodedMap))
// => [ 131, 116, 0, 0, 0, 3, 100, 0, 1, 97, 97, 1, 100, 0, 1, 98, 109, 0, 0, 0, 6, 104, 101, 108, 108, 111, 33, 100, 0, 1, 99, 108, 0, 0, 0, 3, 97, 1, 97, 2, 97, 3, 106 ]
`

#### Lists

Javascript arrays map to Erlang Lists

`javascript
const Bert = require('bert-elixir')

const arrayToEncode = ['hello', 'world', 32, [{ key: "value" }]]
const encodedArray = Bert.encode(arrayToEncode)

console.log(Bert.binaryToList(encodedArray))
`

Todo:
- [ ] Write docs for rest of data types
- [ ] Return nil as null instead of 'nil'
- [ ] Add support for NEW_FLOAT_EXT

--------------------------------


$3

Decoding is typically much simpler than encoding. Just pass the given Binary Erlang Term:

`javascript
const Bert = require('bert-elixir')

// We're showing the term as an array of bytes here for clarity.
// You'll more likely have a string
const erlangTerm = [131, 116, 0, 0, 0, 3, 100, 0, 1, 97, 97, 1, 100, 0, 1, 98, 97, 2, 100, 0, 1, 99, 116, 0, 0, 0, 1, 100, 0, 4, 119, 111, 97, 104, 109, 0, 0, 0, 8, 97, 32, 115, 116, 114, 105, 110, 103]
.map(x => String.fromCharCode(x)).join('') // Convert the array to a string

const decoded = Bert.decode(erlangTerm)

console.log(decoded)
// => { a: 1, b: 2, c: { woah: 'a string' } }
``