fix red code when string template arg is exactly at start/end

need to combine prefix/suffix for whole injection with this particular arg

Author: undeadcat

src/main/kotlin/com/intellij/StyledComponents/StyledComponentsInjector.kt

@@ -40,8 +40,8 @@ class StyledComponentsInjector : MultiHostInjector {
             val stringPlaces = getInjectionPlaces(injectionHost)
             registrar.startInjecting(LESSLanguage.INSTANCE)
             stringPlaces.forEachIndexed { index, (prefix, range, suffix) ->
-                val thePrefix = if (index == 0) acceptedPattern.prefix else prefix
-                val theSuffix = if (index == stringPlaces.size - 1) acceptedPattern.suffix else suffix
+                val thePrefix = if (index == 0) acceptedPattern.prefix + prefix.orEmpty() else prefix
+                val theSuffix = if (index == stringPlaces.size - 1) suffix.orEmpty() + acceptedPattern.suffix else suffix
                 registrar.addPlace(thePrefix, theSuffix, injectionHost, range)
             }
             registrar.doneInjecting()
@@ -61,6 +61,6 @@ class StyledComponentsInjector : MultiHostInjector {
         else result[result.size - 1]
     }
     data class PlaceInfo(val elementPattern: ElementPattern<JSStringTemplateExpression>,
-                         val prefix: String? = null,
-                         val suffix: String? = null)
+                         val prefix: String = "",
+                         val suffix: String = "")
 }

src/main/resources/META-INF/plugin.xml

@@ -1,7 +1,7 @@
 <idea-plugin>
     <id>com.deadlock.scsyntax</id>
     <name>Styled Components</name>
-    <version>1.0.1</version>
+    <version>1.0.2</version>
     <vendor email="[email protected]" url="http://www.saraya.io">Kodehouse</vendor>
 
     <!-- Enable plugin for all products -->

src/test/InjectionTest.kt

@@ -100,12 +100,18 @@ class InjectionTest : LightCodeInsightFixtureTestCase() {
                 "  }\n")
     }
 
-    private fun doTest(fileContent: String, expected: String) {
+    fun testTemplateArgsAtStartEndOfString() {
+        doTest("let atStart = styled.div`\${getPropName()}:red`\n" +
+                "let atEnd = styled.div`color:\${getColor()}`\n",
+                "div {EXTERNAL_FRAGMENT:red}",
+                "div {color:EXTERNAL_FRAGMENT}")
+    }
+
+    private fun doTest(fileContent: String, vararg expected: String) {
         myFixture.setCaresAboutInjection(true)
         val file = myFixture.configureByText("dummy.es6", fileContent)
         val injections = collectInjectedPsiContents(file)
-        Assert.assertEquals(1, injections.size)
-        Assert.assertEquals(expected, injections[0])
+        Assert.assertEquals(expected.toList(), injections)
     }
 
     private fun collectInjectedPsiContents(file: PsiFile): List<String> {