dependencies: [
.package(url: "https://github.com/SoftwareEngineerChris/Consolidate.git", from: "1.0.0")
]let allTaxes = [
TaxAmount(name: "Import Tax", amount: 3.00),
TaxAmount(name: "Sales Tax", amount: 1.75),
TaxAmount(name: "Import Tax", amount: 2.30)
]
let consolidatedTaxes = allTaxes.consolidated(by: \.name) {
TaxAmount(tax: $0.name, amount: $0.amount + $1.amount)
}
// Would result in:
let consolidatedTaxes = [
TaxAmount(name: "Import Tax", amount: 5.30),
TaxAmount(name: "Sales Tax", amount: 4.10)
]let allTaxes = [
TaxAmount(name: "Import Tax", amount: 3.00),
TaxAmount(name: "Sales Tax", amount: 1.75),
TaxAmount(name: "Import Tax", amount: 2.30)
]
let consolidatedTaxes = allTaxes.consolidated(by: { $0.name == $1.name }) {
TaxAmount(tax: $0.name, amount: $0.amount + $1.amount)
}
// Would result in:
let consolidatedTaxes = [
TaxAmount(name: "Import Tax", amount: 5.30),
TaxAmount(name: "Sales Tax", amount: 4.10)
]struct TaxAmount: Consolidatable {
let name: String
let amount: Decimal
var consolidationGroup: AnyHashable {
return name
}
func consolidate(with other: Self) -> Self {
return .init(name: name, amount: amount + other.amount)
}
}The above implementation would consolidate like this:
let taxes = [
TaxAmount(name: "Import Tax", amount: 3.00),
TaxAmount(name: "Sales Tax", amount: 1.75),
TaxAmount(name: "Import Tax", amount: 2.30)
].consolidated()
// Results in:
let taxes = [
TaxAmount(name: "Import Tax", amount: 5.30),
TaxAmount(name: "Sales Tax", amount: 4.10)
]There may be times where you want to consolidate a collection of elements into a single element.
For this, there exists the array extension consolidatedIntoSingle. It is functionally similar to the other
consolidation methods, except its return type is of type Element rather than [Element]. This means that
the collection has to be consolidatable to a single element. If the collection can't be consolidated to a single
element, then the method will throw the error ConsolidationError.couldNotBeConolidatedIntoSingleElement.
let allTaxes = [
TaxAmount(name: "Import Tax", amount: 3.00),
TaxAmount(name: "Sales Tax", amount: 1.75),
TaxAmount(name: "Import Tax", amount: 2.30)
]
// The line below would throw `ConsolidationError.couldNotBeConolidatedIntoSingleElement`,
// since the taxes can't be consolidated into a single tax when using the name key-path.
let consolidatedTax = try allTaxes.consolidatedIntoSingle(by: \.name) {
TaxAmount(tax: $0.name, amount: $0.amount + $1.amount)
}Whereas:
let allTaxes = [
TaxAmount(name: "Import Tax", amount: 3.00),
TaxAmount(name: "Import Tax", amount: 2.30)
]
let consolidatedTax = try allTaxes.consolidatedIntoSingle(by: \.name) {
TaxAmount(tax: $0.name, amount: $0.amount + $1.amount)
}
// Since all taxes have the name "Import Tax", they can be consolidated into a single tax
// when using the name key-path. The result would be:
let consolidatedTax = [
TaxAmount(name: "Import Tax", amount: 5.30)
]