diff --git a/src/common.ts b/src/common.ts
index 31912656..5ddef236 100644
--- a/src/common.ts
+++ b/src/common.ts
@@ -134,6 +134,7 @@ export namespace CommonSymbols {
   export const boolean = "boolean";
   export const string = "string";
   export const native = "native";
+  export const valueof = "valueof";
   // aliases
   export const null_ = "null";
   export const true_ = "true";
diff --git a/src/program.ts b/src/program.ts
index 683fd2f6..f354e347 100644
--- a/src/program.ts
+++ b/src/program.ts
@@ -567,6 +567,12 @@ export class Program extends DiagnosticEmitter {
       this.makeNativeTypeDeclaration(CommonSymbols.native, CommonFlags.EXPORT | CommonFlags.GENERIC),
       DecoratorFlags.BUILTIN
     ));
+    this.nativeFile.add(CommonSymbols.valueof, new TypeDefinition(
+      CommonSymbols.valueof,
+      this.nativeFile,
+      this.makeNativeTypeDeclaration(CommonSymbols.valueof, CommonFlags.EXPORT | CommonFlags.GENERIC),
+      DecoratorFlags.BUILTIN
+    ));
     if (options.hasFeature(Feature.SIMD)) this.registerNativeType(CommonSymbols.v128, Type.v128);
 
     // register compiler hints
diff --git a/src/resolver.ts b/src/resolver.ts
index cdc7857e..9ccb32cb 100644
--- a/src/resolver.ts
+++ b/src/resolver.ts
@@ -212,10 +212,10 @@ export class Resolver extends DiagnosticEmitter {
     var typeNode = <TypeNode>node;
     var typeName = typeNode.name;
     var typeArgumentNodes = typeNode.typeArguments;
-    var possiblyPlaceholder = !typeName.next;
+    var isSimpleType = !typeName.next;
 
-    // look up in contextual type arguments if possibly a placeholder
-    if (possiblyPlaceholder) {
+    // look up in contextual type arguments if a simple type
+    if (isSimpleType) {
       if (contextualTypeArguments && contextualTypeArguments.has(typeName.identifier.text)) {
         let type = contextualTypeArguments.get(typeName.identifier.text)!;
         if (typeArgumentNodes !== null && typeArgumentNodes.length) {
@@ -314,41 +314,11 @@ export class Resolver extends DiagnosticEmitter {
         return type;
       }
 
-      // handle special native type
-      if (possiblyPlaceholder && typeName.identifier.text == CommonSymbols.native) {
-        if (!(typeArgumentNodes && typeArgumentNodes.length == 1)) {
-          if (reportMode == ReportMode.REPORT) {
-            this.error(
-              DiagnosticCode.Expected_0_type_arguments_but_got_1,
-              typeNode.range, "1", (typeArgumentNodes ? typeArgumentNodes.length : 1).toString(10)
-            );
-          }
-          return null;
-        }
-        let typeArgument = this.resolveType(
-          typeArgumentNodes[0],
-          context,
-          contextualTypeArguments,
-          reportMode
-        );
-        if (!typeArgument) return null;
-        switch (typeArgument.kind) {
-          case TypeKind.I8:
-          case TypeKind.I16:
-          case TypeKind.I32: return Type.i32;
-          case TypeKind.ISIZE: if (!this.program.options.isWasm64) return Type.i32;
-          case TypeKind.I64: return Type.i64;
-          case TypeKind.U8:
-          case TypeKind.U16:
-          case TypeKind.U32:
-          case TypeKind.BOOL: return Type.u32;
-          case TypeKind.USIZE: if (!this.program.options.isWasm64) return Type.u32;
-          case TypeKind.U64: return Type.u64;
-          case TypeKind.F32: return Type.f32;
-          case TypeKind.F64: return Type.f64;
-          case TypeKind.V128: return Type.v128;
-          case TypeKind.VOID: return Type.void;
-          default: assert(false);
+      // handle built-in types
+      if (isSimpleType) {
+        switch (typeName.identifier.symbol) {
+          case CommonSymbols.native: return this.resolveBuiltinNativeType(typeNode, context, contextualTypeArguments, reportMode);
+          case CommonSymbols.valueof: return this.resolveBuiltinValueofType(typeNode, context, contextualTypeArguments, reportMode)
         }
       }
 
@@ -402,6 +372,110 @@ export class Resolver extends DiagnosticEmitter {
     return null;
   }
 
+  private resolveBuiltinNativeType(
+    /** The type to resolve. */
+    typeNode: TypeNode,
+    /** Relative context. */
+    context: Element,
+    /** Type arguments inherited through context, i.e. `T`. */
+    contextualTypeArguments: Map<string,Type> | null = null,
+    /** How to proceed with eventualy diagnostics. */
+    reportMode: ReportMode = ReportMode.REPORT
+  ): Type | null {
+    var typeArgumentNodes = typeNode.typeArguments;
+    if (!(typeArgumentNodes && typeArgumentNodes.length == 1)) {
+      if (reportMode == ReportMode.REPORT) {
+        this.error(
+          DiagnosticCode.Expected_0_type_arguments_but_got_1,
+          typeNode.range, "1", (typeArgumentNodes ? typeArgumentNodes.length : 1).toString(10)
+        );
+      }
+      return null;
+    }
+    var typeArgument = this.resolveType(typeArgumentNodes[0], context, contextualTypeArguments, reportMode);
+    if (!typeArgument) return null;
+    switch (typeArgument.kind) {
+      case TypeKind.I8:
+      case TypeKind.I16:
+      case TypeKind.I32: return Type.i32;
+      case TypeKind.ISIZE: if (!this.program.options.isWasm64) return Type.i32;
+      case TypeKind.I64: return Type.i64;
+      case TypeKind.U8:
+      case TypeKind.U16:
+      case TypeKind.U32:
+      case TypeKind.BOOL: return Type.u32;
+      case TypeKind.USIZE: if (!this.program.options.isWasm64) return Type.u32;
+      case TypeKind.U64: return Type.u64;
+      case TypeKind.F32: return Type.f32;
+      case TypeKind.F64: return Type.f64;
+      case TypeKind.V128: return Type.v128;
+      case TypeKind.VOID: return Type.void;
+      default: assert(false);
+    }
+    return null;
+  }
+
+  private resolveBuiltinValueofType(
+    /** The type to resolve. */
+    typeNode: TypeNode,
+    /** Relative context. */
+    context: Element,
+    /** Type arguments inherited through context, i.e. `T`. */
+    contextualTypeArguments: Map<string,Type> | null = null,
+    /** How to proceed with eventualy diagnostics. */
+    reportMode: ReportMode = ReportMode.REPORT
+  ): Type | null {
+    var typeArgumentNodes = typeNode.typeArguments;
+    if (!(typeArgumentNodes && typeArgumentNodes.length == 1)) {
+      if (reportMode == ReportMode.REPORT) {
+        this.error(
+          DiagnosticCode.Expected_0_type_arguments_but_got_1,
+          typeNode.range, "1", (typeArgumentNodes ? typeArgumentNodes.length : 1).toString(10)
+        );
+      }
+      return null;
+    }
+    var typeArgument = this.resolveType(typeArgumentNodes[0], context, contextualTypeArguments, reportMode);
+    if (!typeArgument) return null;
+    var classReference = typeArgument.classReference;
+    if (!classReference) {
+      if (reportMode == ReportMode.REPORT) {
+        this.error(
+          DiagnosticCode.Index_signature_is_missing_in_type_0,
+          typeArgumentNodes[0].range, typeArgument.toString()
+        );
+      }
+      return null;
+    }
+    var program = this.program;
+    var mapPrototype = program.mapPrototype;
+    var setPrototype = program.setPrototype;
+    var arrayPrototype = program.arrayPrototype;
+    if (classReference.extends(arrayPrototype)) {
+      let actualTypeArguments = assert(classReference.getTypeArgumentsTo(arrayPrototype));
+      assert(actualTypeArguments.length == 1);
+      return actualTypeArguments[0];
+    } else if (classReference.extends(mapPrototype)) {
+      let actualTypeArguments = assert(classReference.getTypeArgumentsTo(arrayPrototype));
+      assert(actualTypeArguments.length == 2);
+      return actualTypeArguments[1];
+    } else if (classReference.extends(setPrototype)) {
+      let actualTypeArguments = assert(classReference.getTypeArgumentsTo(arrayPrototype));
+      assert(actualTypeArguments.length == 1);
+      return actualTypeArguments[0];
+    } else {
+      let overload = classReference.lookupOverload(OperatorKind.INDEXED_GET);
+      if (overload) return overload.signature.returnType;
+      if (reportMode == ReportMode.REPORT) {
+        this.error(
+          DiagnosticCode.Index_signature_is_missing_in_type_0,
+          typeArgumentNodes[0].range, typeArgument.toString()
+        );
+      }
+      return null;
+    }
+  }
+
   /** Resolves a type name to the program element it refers to. */
   resolveTypeName(
     /** The type name to resolve. */
diff --git a/std/assembly/index.d.ts b/std/assembly/index.d.ts
index 02b7ccde..71c57a2a 100644
--- a/std/assembly/index.d.ts
+++ b/std/assembly/index.d.ts
@@ -882,6 +882,8 @@ declare namespace v8x16 {
 }
 /** Macro type evaluating to the underlying native WebAssembly type. */
 declare type native<T> = T;
+/** Special type evaluating the value type of a collection. */
+declare type valueof<T extends unknown[]> = T[0];
 
 /** Pseudo-class representing the backing class of integer types. */
 declare class _Integer {
diff --git a/std/assembly/typedarray.ts b/std/assembly/typedarray.ts
index 3965de71..493dc6d2 100644
--- a/std/assembly/typedarray.ts
+++ b/std/assembly/typedarray.ts
@@ -1068,7 +1068,7 @@ function FOREACH<TArray extends ArrayBufferView, T>(
 
 // @ts-ignore: decorator
 @inline
-export function REVERSE<TArray extends ArrayBufferView, T>(array: TArray): TArray {
+function REVERSE<TArray extends ArrayBufferView, T>(array: TArray): TArray {
   var dataStart = array.dataStart;
   for (let front = 0, back = array.length - 1; front < back; ++front, --back) {
     let frontPtr = dataStart + (<usize>front << alignof<T>());
diff --git a/std/portable/index.d.ts b/std/portable/index.d.ts
index ab049ee3..67552f8d 100644
--- a/std/portable/index.d.ts
+++ b/std/portable/index.d.ts
@@ -28,6 +28,9 @@ declare type usize = number;
 declare type f32 = number;
 declare type f64 = number;
 
+/** Special type evaluating the value type of a collection. */
+declare type valueof<T extends unknown[]> = T[0];
+
 // Compiler hints
 
 /** Compiler target. 0 = JS, 1 = WASM32, 2 = WASM64. */
diff --git a/tests/compiler/valueof.json b/tests/compiler/valueof.json
new file mode 100644
index 00000000..b1da366f
--- /dev/null
+++ b/tests/compiler/valueof.json
@@ -0,0 +1,5 @@
+{
+  "asc_flags": [
+    "--runtime none"
+  ]
+}
\ No newline at end of file
diff --git a/tests/compiler/valueof.optimized.wat b/tests/compiler/valueof.optimized.wat
new file mode 100644
index 00000000..e396f28a
--- /dev/null
+++ b/tests/compiler/valueof.optimized.wat
@@ -0,0 +1,9 @@
+(module
+ (type $FUNCSIG$v (func))
+ (memory $0 1)
+ (data (i32.const 8) "\14\00\00\00\01\00\00\00\01\00\00\00\14\00\00\00v\00a\00l\00u\00e\00o\00f\00.\00t\00s")
+ (export "memory" (memory $0))
+ (func $start (; 0 ;) (type $FUNCSIG$v)
+  nop
+ )
+)
diff --git a/tests/compiler/valueof.ts b/tests/compiler/valueof.ts
new file mode 100644
index 00000000..ee200c22
--- /dev/null
+++ b/tests/compiler/valueof.ts
@@ -0,0 +1,26 @@
+// simple
+assert(isInteger<valueof<i8[]>>());
+assert(isSigned<valueof<i8[]>>());
+assert(sizeof<valueof<i8[]>>() == 1);
+
+// alias
+type u32Array = u32[];
+assert(isInteger<valueof<u32Array>>());
+assert(!isSigned<valueof<u32Array>>());
+assert(sizeof<valueof<u32Array>>() == 4);
+
+// float
+assert(isFloat<valueof<f32[]>>());
+assert(sizeof<valueof<f32[]>>() == 4);
+
+// string
+assert(isString<valueof<string[]>>());
+assert(isManaged<valueof<string[]>>());
+
+// array
+assert(isArray<valueof<string[][]>>());
+
+// typed array
+assert(isInteger<valueof<Uint8ClampedArray>>());
+assert(!isSigned<valueof<Uint8ClampedArray>>());
+assert(sizeof<valueof<Uint8ClampedArray>>() == 1);
diff --git a/tests/compiler/valueof.untouched.wat b/tests/compiler/valueof.untouched.wat
new file mode 100644
index 00000000..43cb6cdc
--- /dev/null
+++ b/tests/compiler/valueof.untouched.wat
@@ -0,0 +1,168 @@
+(module
+ (type $FUNCSIG$viiii (func (param i32 i32 i32 i32)))
+ (type $FUNCSIG$v (func))
+ (import "env" "abort" (func $~lib/builtins/abort (param i32 i32 i32 i32)))
+ (memory $0 1)
+ (data (i32.const 8) "\14\00\00\00\01\00\00\00\01\00\00\00\14\00\00\00v\00a\00l\00u\00e\00o\00f\00.\00t\00s\00")
+ (table $0 1 funcref)
+ (elem (i32.const 0) $null)
+ (export "memory" (memory $0))
+ (start $start)
+ (func $start:valueof (; 1 ;) (type $FUNCSIG$v)
+  i32.const 1
+  i32.eqz
+  if
+   i32.const 0
+   i32.const 24
+   i32.const 2
+   i32.const 0
+   call $~lib/builtins/abort
+   unreachable
+  end
+  i32.const 1
+  i32.eqz
+  if
+   i32.const 0
+   i32.const 24
+   i32.const 3
+   i32.const 0
+   call $~lib/builtins/abort
+   unreachable
+  end
+  i32.const 1
+  i32.const 1
+  i32.eq
+  i32.eqz
+  if
+   i32.const 0
+   i32.const 24
+   i32.const 4
+   i32.const 0
+   call $~lib/builtins/abort
+   unreachable
+  end
+  i32.const 1
+  i32.eqz
+  if
+   i32.const 0
+   i32.const 24
+   i32.const 8
+   i32.const 0
+   call $~lib/builtins/abort
+   unreachable
+  end
+  i32.const 0
+  i32.eqz
+  i32.eqz
+  if
+   i32.const 0
+   i32.const 24
+   i32.const 9
+   i32.const 0
+   call $~lib/builtins/abort
+   unreachable
+  end
+  i32.const 4
+  i32.const 4
+  i32.eq
+  i32.eqz
+  if
+   i32.const 0
+   i32.const 24
+   i32.const 10
+   i32.const 0
+   call $~lib/builtins/abort
+   unreachable
+  end
+  i32.const 1
+  i32.eqz
+  if
+   i32.const 0
+   i32.const 24
+   i32.const 13
+   i32.const 0
+   call $~lib/builtins/abort
+   unreachable
+  end
+  i32.const 4
+  i32.const 4
+  i32.eq
+  i32.eqz
+  if
+   i32.const 0
+   i32.const 24
+   i32.const 14
+   i32.const 0
+   call $~lib/builtins/abort
+   unreachable
+  end
+  i32.const 1
+  i32.eqz
+  if
+   i32.const 0
+   i32.const 24
+   i32.const 17
+   i32.const 0
+   call $~lib/builtins/abort
+   unreachable
+  end
+  i32.const 1
+  i32.eqz
+  if
+   i32.const 0
+   i32.const 24
+   i32.const 18
+   i32.const 0
+   call $~lib/builtins/abort
+   unreachable
+  end
+  i32.const 1
+  i32.eqz
+  if
+   i32.const 0
+   i32.const 24
+   i32.const 21
+   i32.const 0
+   call $~lib/builtins/abort
+   unreachable
+  end
+  i32.const 1
+  i32.eqz
+  if
+   i32.const 0
+   i32.const 24
+   i32.const 24
+   i32.const 0
+   call $~lib/builtins/abort
+   unreachable
+  end
+  i32.const 0
+  i32.eqz
+  i32.eqz
+  if
+   i32.const 0
+   i32.const 24
+   i32.const 25
+   i32.const 0
+   call $~lib/builtins/abort
+   unreachable
+  end
+  i32.const 1
+  i32.const 1
+  i32.eq
+  i32.eqz
+  if
+   i32.const 0
+   i32.const 24
+   i32.const 26
+   i32.const 0
+   call $~lib/builtins/abort
+   unreachable
+  end
+ )
+ (func $start (; 2 ;) (type $FUNCSIG$v)
+  call $start:valueof
+ )
+ (func $null (; 3 ;) (type $FUNCSIG$v)
+ )
+)