This section gives you an overview of the functionality of the JavaScript Functions client. The client includes functionality to retrieve all lambdas and to invoke them via a lambda UUID or event ID.

The full documentation can be found in its GitHub repository here.

Setting up the client

Step 1: Set authentication method

For our default implementation we use OAuth 2.0 with Client Credentials. Thus you will have to generate a client ID and client secret using this guide. Alternatively you can provide your own method of authentication. This could come in handy if you want to use the method getLambdas as it does not support our default authentication (OAuth 2.0) yet but still relies on OAuth 1.0. By passing your own implementation to the client you can still generate headers valid for OAuth 1.0.

Step 2: Install the client

yarn add @liveperson/functions-client


npm install @liveperson/functions-client

Provided Methods

The following methods functionality is provided:

  • invoke which allows to call a function by its specific UUID or invoke all functions that implement a specific event
  • isImplemented which allows to test whether a method, that implements a given event, exists
  • getLambdas which returns all lambdas belonging to the user account specified in the client

More detailed documentation can be found here.

Error handling

Errors with the name FaaSLambdaError are raised when the invocation fails due to a custom implementation error. The client internally uses verror. We recommend to log the stack in order to get detailed information about the root cause.

try {
  // invoke here
} catch (error) {
   * LivePerson FunctionsLambdaErrors occur when the lambda fails due to the implementation.
   * These exceptions are not relevant for alerting, because there are no issues with the service itself.
  if ( === "FaaSLambdaError") {, "Error caused by implementation of lambda.");
  } else {
    console.error(error.stack, "Something unexpected happened.");

More detailed information on errors that can occur can be found here.