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

59 lines
2.4 KiB
Swift

import Foundation
import SourceKittenFramework
public struct FirstWhereRule: CallPairRule, OptInRule, ConfigurationProviderRule, AutomaticTestableRule {
public var configuration = SeverityConfiguration(.warning)
public init() {}
public static let description = RuleDescription(
identifier: "first_where",
name: "First Where",
description: "Prefer using `.first(where:)` over `.filter { }.first` in collections.",
kind: .performance,
nonTriggeringExamples: [
"kinds.filter(excludingKinds.contains).isEmpty && kinds.first == .identifier\n",
"myList.first(where: { $0 % 2 == 0 })\n",
"match(pattern: pattern).filter { $0.first == .identifier }\n",
"(myList.filter { $0 == 1 }.suffix(2)).first\n",
"collection.filter(\"stringCol = '3'\").first",
"realm?.objects(User.self).filter(NSPredicate(format: \"email ==[c] %@\", email)).first",
"if let pause = timeTracker.pauses.filter(\"beginDate < %@\", beginDate).first { print(pause) }"
],
triggeringExamples: [
"↓myList.filter { $0 % 2 == 0 }.first\n",
"↓myList.filter({ $0 % 2 == 0 }).first\n",
"↓myList.map { $0 + 1 }.filter({ $0 % 2 == 0 }).first\n",
"↓myList.map { $0 + 1 }.filter({ $0 % 2 == 0 }).first?.something()\n",
"↓myList.filter(someFunction).first\n",
"↓myList.filter({ $0 % 2 == 0 })\n.first\n",
"(↓myList.filter { $0 == 1 }).first\n"
]
)
public func validate(file: SwiftLintFile) -> [StyleViolation] {
return validate(
file: file,
pattern: "[\\}\\)]\\s*\\.first",
patternSyntaxKinds: [.identifier],
callNameSuffix: ".filter",
severity: configuration.severity
) { dictionary in
if
!dictionary.substructure.isEmpty &&
dictionary.substructure.last?.expressionKind != .argument &&
dictionary.substructure.last?.name != "NSPredicate"
{
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)
}
}
}