add isEmpty tag (#118)

vapor · Mar 6, 2023 · 1eddd30 · 1eddd30
1 parent 139fcd5
commit 1eddd30
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diff --git a/Sources/LeafKit/LeafSyntax/LeafTag.swift b/Sources/LeafKit/LeafSyntax/LeafTag.swift
@@ -14,6 +14,7 @@ public var defaultTags: [String: LeafTag] = [
     "uppercased": Uppercased(),
     "capitalized": Capitalized(),
     "contains": Contains(),
+    "isEmpty": IsEmpty(),
     "date": DateTag(),
     "count": Count(),
     "comment": Comment(),
@@ -67,6 +68,15 @@ struct Contains: LeafTag {
     }
 }
 
+struct IsEmpty: LeafTag {
+    func render(_ ctx: LeafContext) throws -> LeafData {
+        guard let str = ctx.parameters.first?.string else {
+            throw "unable to check for empty value unexpected data"
+        }
+        return .init(.bool(str.isEmpty))
+    }
+}
+
 struct DateTag: LeafTag {
     func render(_ ctx: LeafContext) throws -> LeafData {
         let formatter = DateFormatter()

diff --git a/Tests/LeafKitTests/TagTests.swift b/Tests/LeafKitTests/TagTests.swift
@@ -117,6 +117,38 @@ class TagTests: XCTestCase {
         """
         try XCTAssertEqual(render(template, ["core": ["Tanner", "Logan", "Gwynne", "Siemen", "Tim"]]), expected)
     }
+
+    func testIsEmpty() throws {
+        let template = """
+        #if(isEmpty(emptyString)):
+            This is an empty string.
+        #endif
+        """
+
+        let expected = """
+
+            This is an empty string.
+
+        """
+        try XCTAssertEqual(render(template, ["emptyString": ""]), expected)
+    }
+
+    func testIsEmptyFalseCase() throws {
+        let template = """
+        #if(isEmpty(nonEmptyString)):
+            This is an empty string.
+        #else:
+            This is not an empty string.
+        #endif
+        """
+
+        let expected = """
+
+            This is not an empty string.
+
+        """
+        try XCTAssertEqual(render(template, ["nonEmptyString": "I'm not empty."]), expected)
+    }
 
     func testContainsTagWithHTML() throws {
         let template = """