build esm module that can be imported from browsers.

closes https://github.com/fiatjaf/nostr-tools/issues/14

.gitignore

@@ -2,3 +2,4 @@ node_modules
 dist
 yarn.lock
 package-lock.json
+nostr.js

README.md

@@ -70,3 +70,20 @@ pool.addRelay('<url>')
 All functions expect bytearrays as hex strings and output bytearrays as hex strings.
 
 For other utils please read the source (for now).
+
+### Using from the browser (if you don't want to use a bundler)
+
+You can import nostr-tools as an ES module. Just add a script tag like this:
+
+```html
+<script type="module">
+  import {generatePrivateKey} from 'https://unpkg.com/nostr-tools/nostr.js'
+  console.log(generatePrivateKey())
+</script>
+```
+
+And import whatever function you would import from `"nostr-tools"` in a bundler.
+
+## License
+
+Public domain.

build.js

@@ -0,0 +1,25 @@
+#!/usr/bin/env node
+
+const esbuild = require('esbuild')
+const alias = require('esbuild-plugin-alias')
+const nodeGlobals = require('@esbuild-plugins/node-globals-polyfill').default
+
+const buildOptions = {
+  entryPoints: ['index.js'],
+  outfile: 'nostr.js',
+  bundle: true,
+  format: 'esm',
+  plugins: [
+    alias({
+      stream: require.resolve('readable-stream')
+    }),
+    nodeGlobals({buffer: true})
+  ],
+  define: {
+    window: 'self',
+    global: 'self'
+  },
+  loader: {'.js': 'jsx'}
+}
+
+esbuild.build(buildOptions).then(() => console.log('build success.'))

keys.js

@@ -1,4 +1,5 @@
 import * as secp256k1 from '@noble/secp256k1'
+import {Buffer} from 'buffer'
 
 export function generatePrivateKey() {
   return Buffer.from(secp256k1.utils.randomPrivateKey()).toString('hex')

package.json

@@ -1,6 +1,6 @@
 {
   "name": "nostr-tools",
-  "version": "0.22.2",
+  "version": "0.23.1",
   "description": "Tools for making a Nostr client.",
   "repository": {
     "type": "git",
@@ -30,7 +30,15 @@
     "client"
   ],
   "devDependencies": {
+    "@esbuild-plugins/node-globals-polyfill": "^0.1.1",
+    "esbuild": "^0.14.38",
+    "esbuild-plugin-alias": "^0.2.1",
     "eslint": "^8.5.0",
-    "eslint-plugin-babel": "^5.3.1"
+    "eslint-plugin-babel": "^5.3.1",
+    "events": "^3.3.0",
+    "readable-stream": "^3.6.0"
+  },
+  "scripts": {
+    "prepublish": "node build.js"
   }
 }

pool.js

@@ -26,27 +26,35 @@ export function relayPool() {
 
   const activeSubscriptions = {}
 
-  const sub = ({cb, filter}, id = Math.random().toString().slice(2)) => {
+  const sub = (
+    {cb, filter, beforeSend},
+    id = Math.random().toString().slice(2)
+  ) => {
     const subControllers = Object.fromEntries(
       Object.values(relays)
         .filter(({policy}) => policy.read)
         .map(({relay}) => [
           relay.url,
-          relay.sub({filter, cb: event => cb(event, relay.url)}, id)
+          relay.sub({filter, cb: event => cb(event, relay.url), beforeSend}, id)
         ])
     )
 
     const activeCallback = cb
     const activeFilters = filter
+    const activeBeforeSend = beforeSend
 
     const unsub = () => {
       Object.values(subControllers).forEach(sub => sub.unsub())
       delete activeSubscriptions[id]
     }
-    const sub = ({cb = activeCallback, filter = activeFilters}) => {
+    const sub = ({
+      cb = activeCallback,
+      filter = activeFilters,
+      beforeSend = activeBeforeSend
+    }) => {
       Object.entries(subControllers).map(([relayURL, sub]) => [
         relayURL,
-        sub.sub({cb, filter}, id)
+        sub.sub({cb, filter, beforeSend}, id)
       ])
       return activeSubscriptions[id]
     }

relay.js

@@ -119,7 +119,10 @@ export function relayConnect(url, onNotice = () => {}, onError = () => {}) {
     ws.send(msg)
   }
 
-  const sub = ({cb, filter}, channel = Math.random().toString().slice(2)) => {
+  const sub = (
+    {cb, filter, beforeSend},
+    channel = Math.random().toString().slice(2)
+  ) => {
     var filters = []
     if (Array.isArray(filter)) {
       filters = filter
@@ -127,16 +130,25 @@ export function relayConnect(url, onNotice = () => {}, onError = () => {}) {
       filters.push(filter)
     }
 
+    if (beforeSend) {
+      const beforeSendResult = beforeSend({filter, relay: url, channel})
+      filters = beforeSendResult.filter
+    }
+
     trySend(['REQ', channel, ...filters])
     channels[channel] = cb
     openSubs[channel] = filters
 
     const activeCallback = cb
     const activeFilters = filters
+    const activeBeforeSend = beforeSend
 
     return {
-      sub: ({cb = activeCallback, filter = activeFilters}) =>
+      sub: ({
-        sub({cb, filter}, channel),
+        cb = activeCallback,
+        filter = activeFilters,
+        beforeSend = activeBeforeSend
+      }) => sub({cb, filter, beforeSend}, channel),
       unsub: () => {
         delete openSubs[channel]
         delete channels[channel]