chore: clean up types

src/lib/index.mts

@@ -1,14 +1,16 @@
-import ArrayIo from './type/ArrayIo.mjs';
-import StringIo from './type/StringIo.mjs';
-import StructIo from './type/StructIo.mjs';
+import ArrayIo, { ArrayOptions } from './type/ArrayIo.mjs';
+import StringIo, { StringOptions } from './type/StringIo.mjs';
+import StructIo, { StructFields, StructOptions } from './type/StructIo.mjs';
 import TlvIo, { TlvValueCallback } from './type/TlvIo.mjs';
 import { getType } from './util.mjs';
 
-const array = (type, options) => new ArrayIo(type, options);
+const array = (type: Function | IoType, options: ArrayOptions) =>
+  new ArrayIo(type, options);
 
-const string = (options) => new StringIo(options);
+const string = (options: StringOptions) => new StringIo(options);
 
-const struct = (fields, options) => new StructIo(fields, options);
+const struct = (fields: StructFields, options: StructOptions) =>
+  new StructIo(fields, options);
 
 const tlv = (
   tagType: IoType,

src/lib/type/ArrayIo.mts

@@ -8,7 +8,7 @@ class ArrayIo implements IoType {
   #type: IoType;
   #options: ArrayOptions;
 
-  constructor(type: IoType, options: ArrayOptions = {}) {
+  constructor(type: Function | IoType, options: ArrayOptions = {}) {
     if (type === undefined) {
       throw new Error('Missing required argument: type');
     }
@@ -65,3 +65,4 @@ class ArrayIo implements IoType {
 }
 
 export default ArrayIo;
+export { ArrayOptions };

src/lib/type/StringIo.mts

@@ -72,3 +72,4 @@ class StringIo implements IoType {
 }
 
 export default StringIo;
+export { StringOptions };

src/lib/type/StructIo.mts

@@ -1,10 +1,16 @@
-import { getStream, getType } from '../util.mjs';
+import { Endianness, getStream, getType } from '../util.mjs';
+
+type StructFields = Record<string, Function | IoType>;
+
+type StructOptions = {
+  endianness?: Endianness;
+};
 
 class StructIo implements IoType {
-  #fields;
-  #options;
+  #fields: StructFields;
+  #options: StructOptions;
 
-  constructor(fields = {}, options = {}) {
+  constructor(fields: StructFields = {}, options: StructOptions = {}) {
     this.#fields = fields;
     this.#options = options;
   }
@@ -57,3 +63,4 @@ class StructIo implements IoType {
 }
 
 export default StructIo;
+export { StructFields, StructOptions };

src/lib/util.mts

@@ -5,22 +5,20 @@ enum Endianness {
   Big = 2,
 }
 
-const getStream = (source, endianness = Endianness.Little): Stream =>
-  isStream(source) ? source : openStream(source, endianness);
+const getStream = (source: Source, endianness = Endianness.Little): Stream =>
+  isStream(source) ? (source as Stream) : openStream(source, endianness);
 
-const getType = (type): IoType => {
-  if (typeof type === 'function') {
-    type = type();
-  }
+const getType = (type: Function | IoType): IoType => {
+  const resolvedType = typeof type === 'function' ? type() : type;
 
-  if (typeof type.read !== 'function') {
+  if (typeof resolvedType.read !== 'function') {
     throw new Error('Missing required function: read');
   }
 
-  return type;
+  return resolvedType;
 };
 
-const resolveValue = (ref, ...objects) => {
+const resolveValue = (ref: number | string, ...objects: object[]) => {
   if (ref === undefined || typeof ref === 'number') {
     return ref;
   }