Add opportunity to use custom prefixes in StyleSheet (JetBrains#3015)

Author: InsanusMokrassar

html/core/src/jsMain/kotlin/org/jetbrains/compose/web/css/StyleSheet.kt

@@ -20,6 +20,9 @@ class CSSRulesHolderState : CSSRulesHolder {
 /**
  * Represents a collection of the css style rules.
  * StyleSheet needs to be mounted.
+ *
+ * @param customPrefix Will be used as prefix with current style. Pass `null` to use default value (classname of realization)
+ *
  * @see [Style]
  *
  * Example:
@@ -38,12 +41,22 @@ class CSSRulesHolderState : CSSRulesHolder {
  * ```
  */
 open class StyleSheet(
+    customPrefix: String?,
     private val rulesHolder: CSSRulesHolder = CSSRulesHolderState(),
-    val usePrefix: Boolean = true,
 ) : StyleSheetBuilder, CSSRulesHolder by rulesHolder {
     private val boundClasses = mutableMapOf<String, CSSRuleDeclarationList>()
+    protected val prefix: String = customPrefix ?: "${this::class.simpleName}-"
+
+    val usePrefix: Boolean = customPrefix == null
+    constructor(
+        rulesHolder: CSSRulesHolder = CSSRulesHolderState(),
+        usePrefix: Boolean = true
+    ) : this(
+        if (usePrefix) null else "",
+        rulesHolder
+    )
 
-    protected fun style(cssRule: CSSBuilder.() -> Unit) = CSSHolder(usePrefix, cssRule)
+    protected fun style(cssRule: CSSBuilder.() -> Unit) = CSSHolder(prefix, cssRule)
 
     /**
      * Example:
@@ -69,7 +82,7 @@ open class StyleSheet(
      *  }
      * ```
      */
-    protected fun keyframes(cssKeyframes: CSSKeyframesBuilder.() -> Unit) = CSSKeyframesHolder(usePrefix, cssKeyframes)
+    protected fun keyframes(cssKeyframes: CSSKeyframesBuilder.() -> Unit) = CSSKeyframesHolder(prefix, cssKeyframes)
 
     companion object {
         private var counter = 0
@@ -88,13 +101,12 @@ open class StyleSheet(
         }
     }
 
-    protected class CSSHolder(private val usePrefix: Boolean, private val cssBuilder: CSSBuilder.() -> Unit) {
+    protected class CSSHolder(private val prefix: String, private val cssBuilder: CSSBuilder.() -> Unit) {
         operator fun provideDelegate(
             sheet: StyleSheet,
             property: KProperty<*>
         ): ReadOnlyProperty<Any?, String> {
-            val sheetName = if (usePrefix) "${sheet::class.simpleName}-" else ""
-            val className = "$sheetName${property.name}"
+            val className = "$prefix${property.name}"
             val selector = object : CSSSelector() {
                 override fun asString() = ".${className}"
             }
@@ -110,15 +122,14 @@ open class StyleSheet(
      * See [keyframes]
      */
     protected class CSSKeyframesHolder(
-        private val usePrefix: Boolean,
+        private val prefix: String,
         private val keyframesBuilder: CSSKeyframesBuilder.() -> Unit
     ) {
         operator fun provideDelegate(
             sheet: StyleSheet,
             property: KProperty<*>
         ): ReadOnlyProperty<Any?, CSSNamedKeyframes> {
-            val sheetName = if (usePrefix) "${sheet::class.simpleName}-" else ""
-            val keyframesName = "$sheetName${property.name}"
+            val keyframesName = "$prefix${property.name}"
             val rule = buildKeyframes(keyframesName, keyframesBuilder)
             sheet.add(rule)
 

html/core/src/jsTest/kotlin/css/AnimationTests.kt

@@ -35,6 +35,28 @@ object AnimationsStyleSheet : StyleSheet() {
     }
 }
 
+class AnimationsStyleSheetWithCustomPrefix(
+    customPrefix: String
+) : StyleSheet(customPrefix) {
+    val bounce by keyframes {
+        from {
+            property("transform", "translateX(50%)")
+        }
+
+        to {
+            property("transform", "translateX(-50%)")
+        }
+    }
+
+    val animationClass by style {
+        animation(bounce) {
+            duration(2.s)
+            timingFunction(AnimationTimingFunction.EaseIn)
+            direction(AnimationDirection.Alternate)
+        }
+    }
+}
+
 @ExperimentalComposeWebApi
 class AnimationTests {
     @Test
@@ -76,4 +98,31 @@ class AnimationTests {
             "Animation class wasn't injected correctly"
         )
     }
+
+    @Test
+    fun animationClassInjectedWithCustomPrefix() = runTest {
+        val customPrefix = "CustomPrefix-"
+        composition {
+            Style(AnimationsStyleSheetWithCustomPrefix(customPrefix))
+        }
+
+        val el = nextChild() as HTMLStyleElement
+        val cssRules = (el.sheet as? CSSStyleSheet)?.cssRules
+        val rules = (0 until (cssRules?.length ?: 0)).map {
+            cssRules?.item(it)?.cssText?.replace("\n", "") ?: ""
+        }
+
+        // TODO: we need to come up with test that not relying on any kind of formatting
+        assertEquals(
+            "@keyframes ${customPrefix}bounce {0% { transform: translateX(50%); }100% { transform: translateX(-50%); }}",
+            rules[0].replace("   0%", "0%").replace("  100%", "100%"),
+            "Animation keyframes wasn't injected correctly"
+        )
+
+        assertEquals(
+            ".${customPrefix}animationClass { animation: 2s ease-in 0s 1 alternate none running ${customPrefix}bounce; }".trimIndent(),
+            rules[1],
+            "Animation class wasn't injected correctly"
+        )
+    }
 }

html/core/src/jsTest/kotlin/css/StyleSheetTests.kt

@@ -42,4 +42,34 @@ class StyleSheetTests {
         )
     }
 
+    @Test
+    fun stylesheetCorrectlyUsingIncomingPrefix() {
+        val testPrefixParent = "test_prefix_parent-"
+        val testPrefixChild = "test_prefix_child-"
+
+        val styleSheet = object : StyleSheet(customPrefix = testPrefixParent) {
+            val someClassName by style {
+                color(Color.red)
+            }
+        }
+
+        val childStyleSheet = object : StyleSheet(customPrefix = testPrefixChild, styleSheet) {
+            val someClassName by style {
+                color(Color.green)
+            }
+        }
+
+        assertContentEquals(
+            listOf(".${testPrefixParent}someClassName { color: red;}", ".${testPrefixChild}someClassName { color: green;}"),
+            styleSheet.serializeRules(),
+            "styleSheet rules"
+        )
+
+        assertContentEquals(
+            listOf(".${testPrefixParent}someClassName { color: red;}", ".${testPrefixChild}someClassName { color: green;}"),
+            childStyleSheet.serializeRules(),
+            "childStyleSheet rules"
+        )
+    }
+
 }