fix: only import reader/writer to decrease bundle size (#69)

We only use the reader/writer classes from protobuf.js so only import those - drops the size of index.min.js in protons-runtime by about 30kb(!).

packages/protons-runtime/src/decode.ts

@@ -1,6 +1,6 @@
 import type { Uint8ArrayList } from 'uint8arraylist'
 import type { Codec } from './codec.js'
-import { reader } from './reader.js'
+import { reader } from './utils.js'
 
 export function decodeMessage <T> (buf: Uint8Array | Uint8ArrayList, codec: Codec<T>): T {
   const r = reader(buf instanceof Uint8Array ? buf : buf.subarray())

packages/protons-runtime/src/encode.ts

@@ -1,5 +1,5 @@
 import type { Codec } from './codec.js'
-import { writer } from './writer.js'
+import { writer } from './utils.js'
 
 export function encodeMessage <T> (message: T, codec: Codec<T>): Uint8Array {
   const w = writer()

packages/protons-runtime/src/index.ts

@@ -18,8 +18,7 @@ export {
 
 export { enumeration } from './codecs/enum.js'
 export { message } from './codecs/message.js'
-export { reader } from './reader.js'
-export { writer } from './writer.js'
+export { reader, writer } from './utils.js'
 export type { Codec, EncodeOptions } from './codec.js'
 
 export interface Writer {

packages/protons-runtime/src/utils.ts

@@ -0,0 +1,63 @@
+// @ts-expect-error no types
+import ReaderClass from 'protobufjs/src/reader.js'
+// @ts-expect-error no types
+import ReaderBufferClass from 'protobufjs/src/reader_buffer.js'
+// @ts-expect-error no types
+import WriterClass from 'protobufjs/src/writer.js'
+// @ts-expect-error no types
+import WriterBufferClass from 'protobufjs/src/writer_buffer.js'
+// @ts-expect-error no types
+import util from 'protobufjs/src/util/minimal.js'
+import type { Reader, Writer } from './index.js'
+
+function configure () {
+  util._configure()
+  ReaderClass._configure(ReaderBufferClass)
+  WriterClass._configure(WriterBufferClass)
+}
+
+// Set up buffer utility according to the environment
+configure()
+
+// monkey patch the reader to add native bigint support
+const methods = [
+  'uint64', 'int64', 'sint64', 'fixed64', 'sfixed64'
+]
+
+function patchReader (obj: any): any {
+  for (const method of methods) {
+    if (obj[method] == null) {
+      continue
+    }
+
+    const original = obj[method]
+    obj[method] = function (): bigint {
+      return BigInt(original.call(this).toString())
+    }
+  }
+
+  return obj
+}
+
+export function reader (buf: Uint8Array): Reader {
+  return patchReader(new ReaderClass(buf))
+}
+
+function patchWriter (obj: any): any {
+  for (const method of methods) {
+    if (obj[method] == null) {
+      continue
+    }
+
+    const original = obj[method]
+    obj[method] = function (val: bigint) {
+      return original.call(this, val.toString())
+    }
+  }
+
+  return obj
+}
+
+export function writer (): Writer {
+  return patchWriter(WriterClass.create())
+}