Add option to return single values wrapped in an array (#30)

jsonpath-core/src/commonMain/kotlin/com/nfeld/jsonpathkt/JsonPath.kt

@@ -1,7 +1,11 @@
 package com.nfeld.jsonpathkt
 
 import com.nfeld.jsonpathkt.json.JsonNode
+import com.nfeld.jsonpathkt.json.JsonType
+import com.nfeld.jsonpathkt.tokens.ArrayAccessorToken
+import com.nfeld.jsonpathkt.tokens.ObjectAccessorToken
 import com.nfeld.jsonpathkt.tokens.Token
+import com.nfeld.jsonpathkt.tokens.WildcardToken
 import kotlin.jvm.JvmInline
 
 @JvmInline
@@ -18,9 +22,29 @@ public value class JsonPath private constructor(
   }
 }
 
-public inline fun <reified T> JsonPath.resolveOrNull(node: JsonNode): T? =
+public inline fun <reified T> JsonPath.resolveOrNull(
+  node: JsonNode,
+  options: ResolutionOptions = ResolutionOptions.Default,
+): T? =
   tokens.fold(
     initial = node,
   ) { valueAtPath: JsonNode?, nextToken: Token ->
     valueAtPath?.let(nextToken::read)
+  }?.let {
+    val isRoot = tokens.isEmpty()
+    val containsWildcard = tokens.any { token -> token is WildcardToken }
+    val lastToken = tokens.lastOrNull()
+    val isAccessingAnObjectOrArray =
+      lastToken is ObjectAccessorToken || lastToken is ArrayAccessorToken
+    val isNodeAnArray = it.type == JsonType.Array
+
+    val wrappingRequired =
+      options.wrapSingleValue &&
+        !containsWildcard &&
+        (isRoot || isAccessingAnObjectOrArray || !isNodeAnArray)
+
+    when {
+      wrappingRequired -> it.copy(element = it.toJsonArray(listOf(it.element)))
+      else -> it
+    }
   }?.element as? T

jsonpath-core/src/commonMain/kotlin/com/nfeld/jsonpathkt/ResolutionOptions.kt

@@ -0,0 +1,9 @@
+package com.nfeld.jsonpathkt
+
+public data class ResolutionOptions(
+  val wrapSingleValue: Boolean = false,
+) {
+  public companion object {
+    public val Default: ResolutionOptions = ResolutionOptions()
+  }
+}

jsonpath-core/src/commonTest/kotlin/com/nfeld/jsonpathkt/path/WrapSingleValueTest.kt

@@ -0,0 +1,85 @@
+package com.nfeld.jsonpathkt.path
+
+import com.nfeld.jsonpathkt.BOOKS_JSON
+import com.nfeld.jsonpathkt.LARGE_JSON
+import com.nfeld.jsonpathkt.ResolutionOptions
+import com.nfeld.jsonpathkt.SMALL_JSON
+import com.nfeld.jsonpathkt.SMALL_JSON_ARRAY
+import com.nfeld.jsonpathkt.asJson
+import com.nfeld.jsonpathkt.kotlinx.resolvePathOrNull
+import io.kotest.matchers.shouldBe
+import kotlinx.serialization.json.JsonElement
+import kotlin.test.Test
+
+class WrapSingleValueTest {
+  @Test
+  fun parse_should_wrap_root_accessor() {
+    SMALL_JSON.resolvePathWrappedOrNull("$") shouldBe "[${SMALL_JSON}]".asJson
+    SMALL_JSON_ARRAY.resolvePathWrappedOrNull("$") shouldBe "[${SMALL_JSON_ARRAY}]".asJson
+  }
+
+  @Test
+  fun parse_should_wrap_array_accessor() {
+    SMALL_JSON_ARRAY.resolvePathWrappedOrNull("$[0]") shouldBe "[1]".asJson
+    SMALL_JSON_ARRAY.resolvePathWrappedOrNull("$[-1]") shouldBe "[${SMALL_JSON}]".asJson
+
+    """
+    |[
+    |  [
+    |    ["A"], ["B"], ["C"]
+    |  ],
+    |  [
+    |    ["D"], ["E"], ["F"]
+    |  ],
+    |  [
+    |    ["G"], ["H"], ["I"]
+    |  ]
+    |]
+    """.trimMargin()
+      .resolvePathWrappedOrNull("$.[1].[2]") shouldBe """[ [ "F" ] ]""".asJson
+  }
+
+  @Test
+  fun parse_should_wrap_object_accessor() {
+    SMALL_JSON.resolvePathWrappedOrNull("key") shouldBe "[5]".asJson
+    SMALL_JSON_ARRAY.resolvePathWrappedOrNull("$[4].key") shouldBe "[5]".asJson
+    LARGE_JSON.resolvePathWrappedOrNull("$[0].tags") shouldBe """[["occaecat","mollit","ullamco","labore","cillum","laboris","qui"]]""".asJson
+  }
+
+  @Test
+  fun parse_should_not_wrap_wildcard_root_accessor() {
+    SMALL_JSON_ARRAY.resolvePathWrappedOrNull("$*") shouldBe SMALL_JSON_ARRAY.asJson
+    SMALL_JSON_ARRAY.resolvePathWrappedOrNull("$.*") shouldBe SMALL_JSON_ARRAY.asJson
+  }
+
+  @Test
+  fun parse_should_not_wrap_wildcard_array_accessor() {
+    """
+    |[
+    |  [
+    |    ["A"], ["B"], ["C"]
+    |  ],
+    |  [
+    |    ["D"], ["E"], ["F"]
+    |  ],
+    |  [
+    |    ["G"], ["H"], ["I"]
+    |  ]
+    |]
+    """.trimMargin()
+      .resolvePathWrappedOrNull("$.[1].*.[0]") shouldBe """[ "D", "E", "F" ]""".asJson
+  }
+
+  @Test
+  fun parse_should_not_wrap_wildcard_object_accessor() {
+    BOOKS_JSON.resolvePathWrappedOrNull("$.store.book.*.author") shouldBe """["Nigel Rees","Evelyn Waugh","Herman Melville","J. R. R. Tolkien"]""".asJson
+  }
+
+  private val resolutionOptions = ResolutionOptions(wrapSingleValue = true)
+
+  private fun String.resolvePathWrappedOrNull(path: String) =
+    asJson.resolvePathWrappedOrNull(path)
+
+  private fun JsonElement.resolvePathWrappedOrNull(path: String) =
+    resolvePathOrNull(path, options = resolutionOptions)
+}

jsonpath-jsonjava/src/main/kotlin/com/nfeld/jsonpathkt/jsonjava/JsonJavaResolution.kt

@@ -1,6 +1,7 @@
 package com.nfeld.jsonpathkt.jsonjava
 
 import com.nfeld.jsonpathkt.JsonPath
+import com.nfeld.jsonpathkt.ResolutionOptions
 import com.nfeld.jsonpathkt.resolveOrNull
 import org.json.JSONArray
 import org.json.JSONObject
@@ -21,32 +22,56 @@ public value class JSONElement(@PublishedApi internal val element: Any) {
   public inline val asStringOrNull: JSONString? get() = element as? JSONString
 }
 
-public fun JSONArray.resolveOrNull(path: JsonPath): JSONElement? = path.resolveOrNull(this)
+public fun JSONArray.resolveOrNull(
+  path: JsonPath,
+  options: ResolutionOptions = ResolutionOptions.Default,
+): JSONElement? = path.resolveOrNull(this, options)
+
 public fun JSONArray.resolveAsStringOrNull(path: JsonPath): String? =
   path.resolveOrNull(this)?.asStringOrNull?.toJSONString()
 
-public fun JSONArray.resolvePathOrNull(path: String): JSONElement? = JsonPath.compile(path).resolveOrNull(this)
+public fun JSONArray.resolvePathOrNull(
+  path: String,
+  options: ResolutionOptions = ResolutionOptions.Default,
+): JSONElement? = JsonPath.compile(path).resolveOrNull(this, options)
+
 public fun JSONArray.resolvePathAsStringOrNull(path: String): String? =
   JsonPath.compile(path).resolveOrNull(this)?.asStringOrNull?.toJSONString()
 
-public fun JSONObject.resolveOrNull(path: JsonPath): JSONElement? = path.resolveOrNull(this)
+public fun JSONObject.resolveOrNull(
+  path: JsonPath,
+  options: ResolutionOptions = ResolutionOptions.Default,
+): JSONElement? = path.resolveOrNull(this, options)
+
 public fun JSONObject.resolveAsStringOrNull(path: JsonPath): String? =
   path.resolveOrNull(this)?.asStringOrNull?.toJSONString()
 
-public fun JSONObject.resolvePathOrNull(path: String): JSONElement? = JsonPath.compile(path).resolveOrNull(this)
+public fun JSONObject.resolvePathOrNull(
+  path: String,
+  options: ResolutionOptions = ResolutionOptions.Default,
+): JSONElement? = JsonPath.compile(path).resolveOrNull(this, options)
+
 public fun JSONObject.resolvePathAsStringOrNull(path: String): String? =
   JsonPath.compile(path).resolveOrNull(this)?.asStringOrNull?.toJSONString()
 
-public fun JsonPath.resolveOrNull(json: JSONArray): JSONElement? = resolveOrNull<Any>(
+public fun JsonPath.resolveOrNull(
+  json: JSONArray,
+  options: ResolutionOptions = ResolutionOptions.Default,
+): JSONElement? = resolveOrNull<Any>(
   OrgJsonNode(json, isWildcardScope = false),
+  options,
 )?.let(::JSONElement)
 
 public fun JsonPath.resolveAsStringOrNull(json: JSONArray): String? = resolveOrNull<Any>(
   OrgJsonNode(json, isWildcardScope = false),
 )?.let(::JSONElement)?.asStringOrNull?.toJSONString()
 
-public fun JsonPath.resolveOrNull(json: JSONObject): JSONElement? = resolveOrNull<Any>(
+public fun JsonPath.resolveOrNull(
+  json: JSONObject,
+  options: ResolutionOptions = ResolutionOptions.Default,
+): JSONElement? = resolveOrNull<Any>(
   OrgJsonNode(json, isWildcardScope = false),
+  options,
 )?.let(::JSONElement)
 
 public fun JsonPath.resolveAsStringOrNull(json: JSONObject): String? = resolveOrNull<Any>(

jsonpath-kotlinx/src/commonMain/kotlin/com/nfeld/jsonpathkt/kotlinx/KotlinxResolution.kt

@@ -1,26 +1,39 @@
 package com.nfeld.jsonpathkt.kotlinx
 
 import com.nfeld.jsonpathkt.JsonPath
+import com.nfeld.jsonpathkt.ResolutionOptions
 import com.nfeld.jsonpathkt.resolveOrNull
 import kotlinx.serialization.json.JsonElement
 import kotlinx.serialization.json.JsonNull
 import kotlinx.serialization.json.JsonPrimitive
 import kotlinx.serialization.json.contentOrNull
 
-public fun JsonElement.resolvePathOrNull(path: String): JsonElement? = JsonPath.compile(path).resolveOrNull(this)
-public fun JsonElement.resolveOrNull(path: JsonPath): JsonElement? = path.resolveOrNull(this)
+public fun JsonElement.resolvePathOrNull(
+  path: String,
+  options: ResolutionOptions = ResolutionOptions.Default,
+): JsonElement? =
+  JsonPath.compile(path).resolveOrNull(this, options)
+
+public fun JsonElement.resolveOrNull(
+  path: JsonPath,
+  options: ResolutionOptions = ResolutionOptions.Default,
+): JsonElement? = path.resolveOrNull(this, options)
 
 public fun JsonElement.resolvePathAsStringOrNull(path: String): String? =
   JsonPath.compile(path).resolveAsStringOrNull(this)
 
 public fun JsonElement.resolveAsStringOrNull(path: JsonPath): String? =
   path.resolveAsStringOrNull(this)
 
-public fun JsonPath.resolveOrNull(json: JsonElement): JsonElement? {
+public fun JsonPath.resolveOrNull(
+  json: JsonElement,
+  options: ResolutionOptions = ResolutionOptions.Default,
+): JsonElement? {
   if (json is JsonNull) return null
 
   return resolveOrNull<JsonElement>(
     KotlinxJsonNode(json, isWildcardScope = false),
+    options,
   )
 }