Implement RandomAccessCollection on JSArrayRef (#30)

* Implement `RandomAccessCollection` on `JSArrayRef`

* Remove unused `Index` typealias

Author: MaxDesiatov

.gitignore

@@ -1,7 +1,7 @@
 dist
 node_modules
 .DS_Store
-/.build
+.build
 /Packages
 /*.xcodeproj
 xcuserdata/

IntegrationTests/TestSuites/Sources/PrimaryTests/main.swift

@@ -100,6 +100,17 @@ Array_Iterator: do {
     try expectEqual(Array(array), expectedProp_4)
 }
 
+Array_RandomAccessCollection: do {
+    let globalObject1 = getJSValue(this: .global, name: "globalObject1")
+    let globalObject1Ref = try expectObject(globalObject1)
+    let prop_4 = getJSValue(this: globalObject1Ref, name: "prop_4")
+    let array = try expectArray(prop_4)
+    let expectedProp_4: [JSValue] = [
+        .number(3), .number(4), .string("str_elm_1"), .number(5),
+    ]
+    try expectEqual([array[0], array[1], array[2], array[3]], expectedProp_4)
+}
+
 Value_Decoder: do {
     struct GlobalObject1: Codable {
         struct Prop1: Codable {

Sources/JavaScriptKit/JSArrayRef.swift

@@ -14,7 +14,7 @@ public class JSArrayRef {
     }
 }
 
-extension JSArrayRef: Sequence {
+extension JSArrayRef: RandomAccessCollection {
     public typealias Element = JSValue
 
     public func makeIterator() -> Iterator {
@@ -37,4 +37,12 @@ extension JSArrayRef: Sequence {
             return value.isNull ? nil : value
         }
     }
+
+    public subscript(position: Int) -> JSValue {
+        ref.get(position)
+    }
+
+    public var startIndex: Int { 0 }
+
+    public var endIndex: Int { ref.length.number.map(Int.init) ?? 0 }
 }