Update JSDocs to match behaviour

[mgriffin-scottlogic]

Added new JSdoc typedef for components of CO2 estimate
Added it as a union for return types that can be total or components
Addresses part of #196

[sfishel18]

i think there are cases where perVisit has a different return type than perByte:

const co2Emission = new co2({
  results: "segment",
});

const bytesSent = 1000 * 1000 * 1000;
const greenHost = false;

console.log(co2Emission.perVisit(bytesSent, greenHost));

the result i'm seeing looks like this:

{
    "consumerDeviceCO2 - first": 154.825749,
    "consumerDeviceCO2 - subsequent": 1.0321716600000002,
    "networkCO2 - first": 41.68385550000001,
    "networkCO2 - subsequent": 0.27789237000000006,
    "productionCO2 - first": 56.570946750000004,
    "productionCO2 - subsequent": 0.3771396450000001,
    "dataCenterCO2 - first": 44.66127375,
    "dataCenterCO2 - subsequent": 0.297741825,
    "total": 299.7267705
}

[mgriffin-scottlogic]

Good spot, I'll have a look at that - might need a unique type for perVisit.
Is there possibly also a bug there? Adding up all of the first values only gives ~297.74, so I assume the total is including the subsequent visit information too. In terms of what you might want to use this for it would make more sense to have "total - first" and "total - subsequent" properties. Or use sub-objects with first and subsequent values for all of them.

[mgriffin-scottlogic]

NVM, I see that both parts of the component are reduced by a percentage so the total is correct. Having separated total components would be a feature request/matter of taste.