feat: support Json5QuoteStrategy (#1)

Author: lisonge

json5/src/commonMain/kotlin/li/songe/json5/EncodeUtil.kt

@@ -7,14 +7,14 @@ import kotlinx.serialization.json.JsonPrimitive
 
 internal fun stringifyKey(key: String, config: Json5EncoderConfig): String {
     if (key.isEmpty() || !config.unquotedKey) {
-        return stringifyString(key, config.singleQuote)
+        return stringifyString(key, config.quoteStrategy)
     }
     if (!isIdStartChar(key[0])) {
-        return stringifyString(key, config.singleQuote)
+        return stringifyString(key, config.quoteStrategy)
     }
     for (c in key) {
         if (!isIdContinueChar(c)) {
-            return stringifyString(key, config.singleQuote)
+            return stringifyString(key, config.quoteStrategy)
         }
     }
     return key
@@ -34,8 +34,8 @@ private val escapeReplacements = hashMapOf(
 )
 
 // https://github.com/json5/json5/blob/b935d4a280eafa8835e6182551b63809e61243b0/lib/stringify.js#L104
-internal fun stringifyString(value: String, singleQuote: Boolean): String {
-    val wrapChar = if (singleQuote) '\'' else '"'
+internal fun stringifyString(value: String, quoteStrategy: Json5QuoteStrategy): String {
+    val wrapChar = if (quoteStrategy.quote(value)) '\'' else '"'
     val sb = StringBuilder()
     sb.append(wrapChar)
     value.forEachIndexed { i, c ->
@@ -71,7 +71,7 @@ internal fun stringifyString(value: String, singleQuote: Boolean): String {
 }
 
 internal fun stringifyPrimitive(value: JsonPrimitive, config: Json5EncoderConfig): String = when {
-    value.isString -> stringifyString(value.content, config.singleQuote)
+    value.isString -> stringifyString(value.content, config.quoteStrategy)
     else -> value.content
 }
 

json5/src/commonMain/kotlin/li/songe/json5/Json5EncoderConfig.kt

@@ -2,7 +2,7 @@ package li.songe.json5
 
 data class Json5EncoderConfig(
     val indent: String = "",
-    val singleQuote: Boolean = true,
+    val quoteStrategy: Json5QuoteStrategy = Json5QuoteStrategy.Single,
     val unquotedKey: Boolean = true,
     val trailingComma: Boolean = false,
 )

json5/src/commonMain/kotlin/li/songe/json5/Json5QuoteStrategy.kt

@@ -0,0 +1,31 @@
+package li.songe.json5
+
+
+@Suppress("unused")
+sealed class Json5QuoteStrategy {
+    /**
+     * - true -> single quote
+     * - false -> double quote
+     */
+    internal abstract fun quote(value: String): Boolean
+
+    data object Single : Json5QuoteStrategy() {
+        override fun quote(value: String) = true
+    }
+
+    data object Double : Json5QuoteStrategy() {
+        override fun quote(value: String) = false
+    }
+
+    data object PreferSingle : Json5QuoteStrategy() {
+        override fun quote(value: String): Boolean {
+            return value.contains('"') || !value.contains('\'')
+        }
+    }
+
+    data object PreferDouble : Json5QuoteStrategy() {
+        override fun quote(value: String): Boolean {
+            return value.contains('"') && !value.contains('\'')
+        }
+    }
+}

json5/src/commonTest/kotlin/li/songe/json5/Json5Test.kt

@@ -12,6 +12,16 @@ class Json5Test {
 
     private fun p(string: String) = Json.parseToJsonElement(string)
 
+    private fun e5(
+        string: String,
+        config: Json5EncoderConfig = Json5EncoderConfig(),
+    ) = Json5.encodeToString(JsonPrimitive(string), config)
+
+    private fun q5(
+        string: String,
+        strategy: Json5QuoteStrategy,
+    ) = e5(string, Json5EncoderConfig(quoteStrategy = strategy))
+
     // https://github.com/json5/json5/blob/main/test/parse.js
     @Test
     fun parse() {
@@ -205,9 +215,6 @@ class Json5Test {
         println("element: $element")
         val option = Json5EncoderConfig(
             indent = "\u0020\u0020",
-            singleQuote = true,
-            unquotedKey = true,
-            trailingComma = false,
         )
         val formatted = Json5.encodeToString(element, option)
         println("formatted:\n$formatted")
@@ -235,4 +242,54 @@ class Json5Test {
         }
         println(htmlText)
     }
+
+    @Test
+    fun quote() {
+        assertEquals(
+            q5(
+                """  "a'  """.trim(),
+                Json5QuoteStrategy.Single,
+            ),
+            """  '"a\''  """.trim(),
+        )
+        assertEquals(
+            q5(
+                """  "a'  """.trim(),
+                Json5QuoteStrategy.Double,
+            ),
+            """  "\"a'"  """.trim(),
+        )
+
+        assertEquals(
+            q5(
+                """  a"  """.trim(),
+                Json5QuoteStrategy.PreferSingle,
+            ),
+            """  'a"'  """.trim(),
+        )
+        assertEquals(
+            q5(
+                """  a'  """.trim(),
+                Json5QuoteStrategy.PreferSingle,
+            ),
+            """  "a'"  """.trim(),
+        )
+
+        assertEquals(
+            q5(
+                """  a'  """.trim(),
+                Json5QuoteStrategy.PreferDouble,
+            ),
+            """  "a'"  """.trim(),
+        )
+
+        assertEquals(
+            q5(
+                """  a"  """.trim(),
+                Json5QuoteStrategy.PreferDouble,
+            ),
+            """  'a"'  """.trim(),
+        )
+
+    }
 }