chore: migrate to TypeScript

This change introduces an ESM build which will allow tree shaking. A
CJS build is also provided for backward compatibility.

Author: darrachequesne

.eslintrc.json

@@ -1,2 +1,3 @@
 node_modules
 .nyc_output
+build/

.gitignore

@@ -14,8 +14,4 @@ Object.keys(PACKET_TYPES).forEach(key => {
 
 const ERROR_PACKET = { type: "error", data: "parser error" };
 
-module.exports = {
-  PACKET_TYPES,
-  PACKET_TYPES_REVERSE,
-  ERROR_PACKET
-};
+export { PACKET_TYPES, PACKET_TYPES_REVERSE, ERROR_PACKET };

lib/commons.js renamed to lib/commons.ts

@@ -1,12 +1,8 @@
-const { PACKET_TYPES_REVERSE, ERROR_PACKET } = require("./commons");
+import { ERROR_PACKET, PACKET_TYPES_REVERSE } from "./commons.js";
+import { decode } from "base64-arraybuffer";
 
 const withNativeArrayBuffer = typeof ArrayBuffer === "function";
 
-let base64decoder;
-if (withNativeArrayBuffer) {
-  base64decoder = require("base64-arraybuffer");
-}
-
 const decodePacket = (encodedPacket, binaryType) => {
   if (typeof encodedPacket !== "string") {
     return {
@@ -36,8 +32,8 @@ const decodePacket = (encodedPacket, binaryType) => {
 };
 
 const decodeBase64Packet = (data, binaryType) => {
-  if (base64decoder) {
-    const decoded = base64decoder.decode(data);
+  if (withNativeArrayBuffer) {
+    const decoded = decode(data);
     return mapBinary(decoded, binaryType);
   } else {
     return { base64: true, data }; // fallback for old browsers
@@ -54,4 +50,4 @@ const mapBinary = (data, binaryType) => {
   }
 };
 
-module.exports = decodePacket;
+export default decodePacket;

lib/decodePacket.browser.js renamed to lib/decodePacket.browser.ts

@@ -1,6 +1,6 @@
-const { PACKET_TYPES_REVERSE, ERROR_PACKET } = require("./commons");
+import { ERROR_PACKET, PACKET_TYPES_REVERSE } from "./commons.js";
 
-const decodePacket = (encodedPacket, binaryType) => {
+const decodePacket = (encodedPacket, binaryType?) => {
   if (typeof encodedPacket !== "string") {
     return {
       type: "message",
@@ -48,4 +48,4 @@ const toArrayBuffer = buffer => {
   return arrayBuffer;
 };
 
-module.exports = decodePacket;
+export default decodePacket;

lib/decodePacket.js renamed to lib/decodePacket.ts

@@ -1,4 +1,4 @@
-const { PACKET_TYPES } = require("./commons");
+import { PACKET_TYPES } from "./commons.js";
 
 const withNativeBlob =
   typeof Blob === "function" ||
@@ -37,10 +37,10 @@ const encodePacket = ({ type, data }, supportsBinary, callback) => {
 const encodeBlobAsBase64 = (data, callback) => {
   const fileReader = new FileReader();
   fileReader.onload = function() {
-    const content = fileReader.result.split(",")[1];
+    const content = (fileReader.result as string).split(",")[1];
     callback("b" + content);
   };
   return fileReader.readAsDataURL(data);
 };
 
-module.exports = encodePacket;
+export default encodePacket;

lib/encodePacket.browser.js renamed to lib/encodePacket.browser.ts

@@ -1,4 +1,4 @@
-const { PACKET_TYPES } = require("./commons");
+import { PACKET_TYPES } from "./commons.js";
 
 const encodePacket = ({ type, data }, supportsBinary, callback) => {
   if (data instanceof ArrayBuffer || ArrayBuffer.isView(data)) {
@@ -24,4 +24,4 @@ const encodeBuffer = (data, supportsBinary) => {
   return supportsBinary ? data : "b" + data.toString("base64");
 };
 
-module.exports = encodePacket;
+export default encodePacket;

lib/encodePacket.js renamed to lib/encodePacket.ts

@@ -1,5 +1,5 @@
-const encodePacket = require("./encodePacket");
-const decodePacket = require("./decodePacket");
+import encodePacket from "./encodePacket.js";
+import decodePacket from "./decodePacket.js";
 
 const SEPARATOR = String.fromCharCode(30); // see https://en.wikipedia.org/wiki/Delimiter#ASCII_delimited_text
 
@@ -20,7 +20,7 @@ const encodePayload = (packets, callback) => {
   });
 };
 
-const decodePayload = (encodedPayload, binaryType) => {
+const decodePayload = (encodedPayload, binaryType?) => {
   const encodedPackets = encodedPayload.split(SEPARATOR);
   const packets = [];
   for (let i = 0; i < encodedPackets.length; i++) {
@@ -33,10 +33,5 @@ const decodePayload = (encodedPayload, binaryType) => {
   return packets;
 };
 
-module.exports = {
-  protocol: 4,
-  encodePacket,
-  encodePayload,
-  decodePacket,
-  decodePayload
-};
+export const protocol = 5;
+export { encodePacket, encodePayload, decodePacket, decodePayload };