What's an operation?

An Operation is a function which returns a function which takes state and returns a Promise or state.

The purpose of an Operation is to act as an unresolved unit of behaviour.

For example, when creating an expression - the code itself doesn't know what the state is going to be, only what it's going to do.

Language packs all follow this convention, where the functions that are provided all return Operations.

create('My_Custom_Object__c', {
  Custom_Field__c: dataValue('foo'),
});

In the snippet above, the create function doesn't know anything about credentials, or any dynamic data that you may be available at runtime.

function create(objectName, data) {
  return function (state) {
    // expand the data argument using state
    // actually do the work
  };
}

In this snippet is a simple example of what most functions in OpenFn look like. The create function returns a function that takes state, this is an Operation. The runtime using execute will call all Operations with state.