diff --git a/libraries/stdlib/js/src/kotlin/collections/ArrayList.kt b/libraries/stdlib/js/src/kotlin/collections/ArrayList.kt
index 582205789bb..b67d9965293 100644
--- a/libraries/stdlib/js/src/kotlin/collections/ArrayList.kt
+++ b/libraries/stdlib/js/src/kotlin/collections/ArrayList.kt
@@ -23,7 +23,8 @@ public actual open class ArrayList<E> internal constructor(private var array: Ar
      * Creates an empty [ArrayList].
      * @param initialCapacity initial capacity (ignored)
      */
-    public actual constructor(initialCapacity: Int) : this(emptyArray()) {}
+    @Suppress("ACTUAL_FUNCTION_WITH_DEFAULT_ARGUMENTS")
+    public actual constructor(initialCapacity: Int = 0) : this(emptyArray()) {}
 
     /**
      * Creates an [ArrayList] filled from the [elements] collection.
diff --git a/libraries/stdlib/js/src/kotlin/collections/HashMap.kt b/libraries/stdlib/js/src/kotlin/collections/HashMap.kt
index 04b0d4b2079..6a49633e795 100644
--- a/libraries/stdlib/js/src/kotlin/collections/HashMap.kt
+++ b/libraries/stdlib/js/src/kotlin/collections/HashMap.kt
@@ -66,10 +66,11 @@ public actual open class HashMap<K, V> : AbstractMutableMap<K, V>, MutableMap<K,
      *
      * @throws IllegalArgumentException if the initial capacity or load factor are negative
      */
-    actual constructor(initialCapacity: Int, loadFactor: Float) : this() {
+    @Suppress("ACTUAL_FUNCTION_WITH_DEFAULT_ARGUMENTS")
+    actual constructor(initialCapacity: Int, loadFactor: Float = 0.0f) : this() {
         // This implementation of HashMap has no need of load factors or capacities.
-        require(initialCapacity >= 0) { "Negative initial capacity" }
-        require(loadFactor >= 0) { "Non-positive load factor" }
+        require(initialCapacity >= 0) { "Negative initial capacity: $initialCapacity" }
+        require(loadFactor >= 0) { "Non-positive load factor: $loadFactor" }
     }
 
     actual constructor(initialCapacity: Int) : this(initialCapacity, 0.0f)
diff --git a/libraries/stdlib/js/src/kotlin/collections/HashSet.kt b/libraries/stdlib/js/src/kotlin/collections/HashSet.kt
index 9eb342ee4d4..31d0aeda740 100644
--- a/libraries/stdlib/js/src/kotlin/collections/HashSet.kt
+++ b/libraries/stdlib/js/src/kotlin/collections/HashSet.kt
@@ -39,7 +39,8 @@ public actual open class HashSet<E> : AbstractMutableSet<E>, MutableSet<E> {
      *
      * @throws IllegalArgumentException if the initial capacity or load factor are negative
      */
-    actual constructor(initialCapacity: Int, loadFactor: Float) {
+    @Suppress("ACTUAL_FUNCTION_WITH_DEFAULT_ARGUMENTS")
+    actual constructor(initialCapacity: Int, loadFactor: Float = 0.0f) {
         map = HashMap<E, Any>(initialCapacity, loadFactor)
     }
 
diff --git a/libraries/stdlib/js/src/kotlin/collections/LinkedHashMap.kt b/libraries/stdlib/js/src/kotlin/collections/LinkedHashMap.kt
index 4093b4ba42f..39e4f7f66cf 100644
--- a/libraries/stdlib/js/src/kotlin/collections/LinkedHashMap.kt
+++ b/libraries/stdlib/js/src/kotlin/collections/LinkedHashMap.kt
@@ -174,7 +174,8 @@ public actual open class LinkedHashMap<K, V> : HashMap<K, V>, MutableMap<K, V> {
      *
      * @throws IllegalArgumentException if the initial capacity or load factor are negative
      */
-    actual constructor(initialCapacity: Int, loadFactor: Float) : super(initialCapacity, loadFactor) {
+    @Suppress("ACTUAL_FUNCTION_WITH_DEFAULT_ARGUMENTS")
+    actual constructor(initialCapacity: Int, loadFactor: Float = 0.0f) : super(initialCapacity, loadFactor) {
         map = HashMap<K, ChainEntry<K, V>>()
     }
 
diff --git a/libraries/stdlib/js/src/kotlin/collections/LinkedHashSet.kt b/libraries/stdlib/js/src/kotlin/collections/LinkedHashSet.kt
index a44344363bd..0dcaf748331 100644
--- a/libraries/stdlib/js/src/kotlin/collections/LinkedHashSet.kt
+++ b/libraries/stdlib/js/src/kotlin/collections/LinkedHashSet.kt
@@ -38,7 +38,8 @@ public actual open class LinkedHashSet<E> : HashSet<E>, MutableSet<E> {
      *
      * @throws IllegalArgumentException if the initial capacity or load factor are negative
      */
-    actual constructor(initialCapacity: Int, loadFactor: Float) : super(LinkedHashMap<E, Any>(initialCapacity, loadFactor))
+    @Suppress("ACTUAL_FUNCTION_WITH_DEFAULT_ARGUMENTS")
+    actual constructor(initialCapacity: Int, loadFactor: Float = 0.0f) : super(LinkedHashMap<E, Any>(initialCapacity, loadFactor))
 
     actual constructor(initialCapacity: Int) : this(initialCapacity, 0.0f)
 
diff --git a/libraries/stdlib/js/src/kotlin/text.kt b/libraries/stdlib/js/src/kotlin/text.kt
index d0e9864bc32..fec1bdfc638 100644
--- a/libraries/stdlib/js/src/kotlin/text.kt
+++ b/libraries/stdlib/js/src/kotlin/text.kt
@@ -12,7 +12,7 @@ public actual interface Appendable {
     public actual fun append(c: Char): Appendable
 }
 
-public actual class StringBuilder(content: String) : Appendable, CharSequence {
+public actual class StringBuilder(content: String = "") : Appendable, CharSequence {
     actual constructor(capacity: Int) : this() {}
 
     actual constructor(content: CharSequence) : this(content.toString()) {}