Programmatically get advanced battery information on Apple devices

BatteryInfo.swift

/// Rewrite of https://gist.github.com/leminlimez/ed3e3ee3a287c503c5b834acdc0dfcdc in Swift (the superior language)
/// NOTE: To use IOKit, you need to create a bridging header with the following contents: `#include <IOKit/IOKitLib.h>`
/// This requires you to have the (private) `systemgroup.com.apple.powerlog` entitlement.
func getBatteryInfo() throws -> [String:Any] {
    var service: io_service_t? // Battery IOService
    service = IOServiceGetMatchingService(kIOMainPortDefault, IOServiceMatching("AppleSmartBattery")) // iPhone 11+
    if service == nil {
        service = IOServiceGetMatchingService(kIOMainPortDefault, IOServiceMatching("IOPMPowerSource")) // Earlier iPhones
    }
    
    if let service {
        defer {IOObjectRelease(service)} // Release IOService on function exit
        
        var prop: Unmanaged<CFMutableDictionary>?
        IORegistryEntryCreateCFProperties(service, &prop, nil, 0) // Get properties
        
        if let prop,
           let dict = prop.takeUnretainedValue() as NSDictionary as? [String:Any] { // shadow typecast dark voodoo magic
            return dict
        } else {
            throw "Could not get battery information." // Either could not get properties or typecast them (take your pick ¯\_(ツ)_/¯)
        }
    } else {
        throw "Could not communicate with IOKit." // Could not get service
    }
}