From 122dc25ce6d0e0a9196e257451bf18096b1d6690 Mon Sep 17 00:00:00 2001
From: Robbie Trencheny <me@robbiet.us>
Date: Tue, 14 May 2019 21:45:41 -0700
Subject: [PATCH] Add a new filter to output a unicode codepoint

---
 Sources/StencilSwiftKit/Environment.swift     | 1 +
 Sources/StencilSwiftKit/Filters+Strings.swift | 8 ++++++++
 2 files changed, 9 insertions(+)

diff --git a/Sources/StencilSwiftKit/Environment.swift b/Sources/StencilSwiftKit/Environment.swift
index d73127ee..00bafd25 100644
--- a/Sources/StencilSwiftKit/Environment.swift
+++ b/Sources/StencilSwiftKit/Environment.swift
@@ -42,6 +42,7 @@ public extension Extension {
     registerFilter("snakeToCamelCase", filter: Filters.Strings.snakeToCamelCase)
     registerFilter("swiftIdentifier", filter: Filters.Strings.swiftIdentifier)
     registerFilter("titlecase", filter: Filters.Strings.upperFirstLetter)
+    registerFilter("unicodeCase", filter: Filters.Strings.unicodeCase)
     registerFilter("upperFirstLetter", filter: Filters.Strings.upperFirstLetter)
     registerFilter("contains", filter: Filters.Strings.contains)
     registerFilter("hasPrefix", filter: Filters.Strings.hasPrefix)
diff --git a/Sources/StencilSwiftKit/Filters+Strings.swift b/Sources/StencilSwiftKit/Filters+Strings.swift
index fde13126..b9a50e26 100644
--- a/Sources/StencilSwiftKit/Filters+Strings.swift
+++ b/Sources/StencilSwiftKit/Filters+Strings.swift
@@ -179,6 +179,14 @@ extension Filters.Strings {
     return result
   }
 
+  static func unicodeCase(value: Any?) throws -> Any? {
+    guard let string = value as? String else { throw Filters.Error.invalidInputType }
+    let escapingCharacterSet = CharacterSet(charactersIn: "\\")
+    let unicode = string.trimmingCharacters(in: escapingCharacterSet)
+
+    return "\\u{" + unicode + "}"
+  }
+
   // MARK: Private
 
   private static func containsAnyLowercasedChar(_ string: String) throws -> Bool {