SwiftLint/Source/SwiftLintFramework/Rules/Performance/LastWhereRule.swift

52 lines
2.0 KiB
Swift

import Foundation
import SourceKittenFramework
public struct LastWhereRule: CallPairRule, OptInRule, ConfigurationProviderRule, AutomaticTestableRule {
public var configuration = SeverityConfiguration(.warning)
public init() {}
public static let description = RuleDescription(
identifier: "last_where",
name: "Last Where",
description: "Prefer using `.last(where:)` over `.filter { }.last` in collections.",
kind: .performance,
minSwiftVersion: .fourDotTwo,
nonTriggeringExamples: [
"kinds.filter(excludingKinds.contains).isEmpty && kinds.last == .identifier\n",
"myList.last(where: { $0 % 2 == 0 })\n",
"match(pattern: pattern).filter { $0.last == .identifier }\n",
"(myList.filter { $0 == 1 }.suffix(2)).last\n",
"collection.filter(\"stringCol = '3'\").last"
],
triggeringExamples: [
"↓myList.filter { $0 % 2 == 0 }.last\n",
"↓myList.filter({ $0 % 2 == 0 }).last\n",
"↓myList.map { $0 + 1 }.filter({ $0 % 2 == 0 }).last\n",
"↓myList.map { $0 + 1 }.filter({ $0 % 2 == 0 }).last?.something()\n",
"↓myList.filter(someFunction).last\n",
"↓myList.filter({ $0 % 2 == 0 })\n.last\n",
"(↓myList.filter { $0 == 1 }).last\n"
]
)
public func validate(file: SwiftLintFile) -> [StyleViolation] {
return validate(file: file,
pattern: "[\\}\\)]\\s*\\.last",
patternSyntaxKinds: [.identifier],
callNameSuffix: ".filter",
severity: configuration.severity) { dictionary in
if !dictionary.substructure.isEmpty {
return true // has a substructure, like a closure
}
guard let bodyRange = dictionary.bodyByteRange else {
return true
}
let syntaxKinds = file.syntaxMap.kinds(inByteRange: bodyRange)
return !syntaxKinds.contains(.string)
}
}
}