diff --git a/implementations/javascript/src/record.ts b/implementations/javascript/src/record.ts
index fc5a350..825b9ce 100644
--- a/implementations/javascript/src/record.ts
+++ b/implementations/javascript/src/record.ts
@@ -77,7 +77,7 @@ export class Record<T extends object = DefaultPointer> extends Array<Value<T>> {
 
     static makeBasicConstructor<T extends object = DefaultPointer>(label: Value<T>, fieldNames: string[]): RecordConstructor<T> {
         const arity = fieldNames.length;
-        const ctor: RecordConstructor<T> = (...fields: any[]): Record<T> => {
+        const ctor: RecordConstructor<T> = (...fields: Value<T>[]): Record<T> => {
             if (fields.length !== arity) {
                 throw new Error("Record: cannot instantiate " + (label && label.toString()) +
                     " expecting " + arity + " fields with " + fields.length + " fields");
@@ -89,7 +89,7 @@ export class Record<T extends object = DefaultPointer> extends Array<Value<T>> {
         ctor.isClassOf = (v: any): v is Record<T> => Record.isClassOf(constructorInfo, v);
         ctor._ = {};
         fieldNames.forEach((name, i) => {
-            ctor._[name] = function (r: any): Value<T> | undefined {
+            ctor._[name] = function (r: Value<T>): Value<T> | undefined {
                 if (!ctor.isClassOf(r)) {
                     throw new Error("Record: attempt to retrieve field "+label.toString()+"."+name+
                         " from non-"+label.toString()+": "+(r && r.toString()));
@@ -121,10 +121,10 @@ export class Record<T extends object = DefaultPointer> extends Array<Value<T>> {
 }
 
 export interface RecordConstructor<T extends object = DefaultPointer> {
-    (...fields: any[]): Record<T>;
+    (...fields: Value<T>[]): Record<T>;
     constructorInfo: RecordConstructorInfo<T>;
     isClassOf(v: any): v is Record<T>;
-    _: { [getter: string]: (r: any) => Value<T> | undefined };
+    _: { [getter: string]: (r: Value<T>) => Value<T> | undefined };
 }
 
 export interface RecordConstructorInfo<T extends object = DefaultPointer> {