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Pact Smart Contract Language API JavaScript wrappers

This package is here to help make interaction with both Pact's development server & a ScalableBFT cluster running Pact easy. The API's for each are the same. For information about Pact & ScalableBFT please see or

For example usage, see


pact-lang-api.js should work as expected as a regular node dependency.

<script src="pact-lang-api-global.min.js"></script> will import the library and inject it as a top-level definition called Pact



Converting between binary & hex formats:

Pact.crypto.binToHex(<Uint8Array>) -> string
Pact.crypto.hexToBin(string) -> Uint8Array

Hashing (blake2b):

Pact.crypto.hash(string) -> string

PPK Signing is done via TweetNacl but with ed25519-donna style keys, represented as hex. blake2b is used to hash the message (), and TweetNacl then signs the hash.

Pact.crypto.genKeyPair() -> {"publicKey": <string>, "secretKey": <string>}
Pact.crypto.sign(<string>, keyPair) -> {"hash": <string>, "sig":<string>, "pubKey":<string>}
Pact.crypto.toTweetNaclSecretKey(keyPair) -> <Uint8Array>

Language Expression Construction

A helper function for constructing native Pact commands.

Pact.lang.mkExp(<string>, *args) -> <string>
  ex: mkExp("todos.edit-todo", 1, "bar") -> '(todos.edit-todo 1 "bar")'

NB: JSON.stringify, which is used here, generally converts floating point numbers correctly but fails for high precision scientific numbers < 0; you will need to manually convert them. e.g. JSON.stringify(.0000001) -> '1e-7' is incorrect as Pact has infinite precision decimals but does not interpret scientific numbers, so the proper conversion would be JSON.stringify(.0000001) -> '0.0000001'

Simple API

A simplified set of functions for working with the api.

## send as POST to /api/send
Pact.simple.exec.createCommand([keyPair], <nonce: string>, <pactCode: string>, <envData: object>) -> {"cmds":[...]}
## send as POST to /api/poll
Pact.simple.exec.createPollRequest({"cmds": [...]}) -> {"requestKeys": [...]}
## send as POST to /api/listen
Pact.simple.exec.createListenRequest({"cmds": [...]}) -> {"requestKey": <string>}

Low Level API

Lower level/internal functions to aid in the construction of JSON blobs that the API endpoints expect. You probably want to use the Pact.simple functions instead of these.

Pact.api.mkSingleCmd([signatures],{cmd-object}) -> {"hash":<string>, "sigs":[signatures], "cmd":cmd}
Pact.api.mkPublicSend([cmd]) -> {"cmds":[cmd]} \\ send as POST to /api/poll