feat(marble): add support for handling multi-letter events

now you can create a stream like `--(ab)--|` which will only fire one event at 20ms and its value
will be `ab`. Earlier this would have emitted multiple events for each charachter — `(,a,b,)`
separated by 10ms.

Author: tusharmath

src/internal/Marble.ts

@@ -18,6 +18,14 @@ export function fromMarble(
     switch (message[i]) {
       case ' ':
         break
+      case '(':
+        let value = ''
+        while (message[++i] !== ')') {
+          value += message[i]
+        }
+        events.push(EVENT.next(time, value))
+        time += size
+        break
       case '-':
         time += size
         break
@@ -55,7 +63,8 @@ export function toMarble<T>(
     while (count-- > 1) message += '-'
     switch (ev.type) {
       case EventType.next:
-        message += (ev as EventNext<T>).value.toString()
+        const s = (ev as EventNext<T>).value.toString()
+        message += s.length > 1 ? `(${s})` : s
         break
       case EventType.error:
         message += '#'

test/test.Marble.ts

@@ -32,12 +32,39 @@ describe('marble()', () => {
 
   it('should ignore whitespaces', () => {
     const message = '   -A B -- C |   '
-
     const actual = toMarble(fromMarble(message))
     const expected = '-AB--C|'
     assert.strictEqual(actual, expected)
   })
 
+  it('should parse multi-letter messages', () => {
+    const message = '   -(ABC)-(PQR)-|'
+    const actual = fromMarble(message)
+    const expected = [
+      EVENT.next(210, 'ABC'),
+      EVENT.next(230, 'PQR'),
+      EVENT.complete(250)
+    ]
+    assert.deepEqual(actual, expected)
+  })
+
+  it('should create multi-letter messages', () => {
+    const actual = toMarble([
+      EVENT.next(210, 'ABC'),
+      EVENT.next(230, 'PQR'),
+      EVENT.complete(250)
+    ])
+    const expected = '-(ABC)-(PQR)-|'
+    assert.deepEqual(actual, expected)
+  })
+
+  it('should interop with multi-letter messages', () => {
+    const test = '--a--(bc)--p(qr)--|'
+    const actual = toMarble(fromMarble(test))
+    const expected = test
+    assert.strictEqual(actual, expected)
+  })
+
   it('should auto convert values to numbers if possible', () => {
     const message = '--1-2-3-4'
     const actual = fromMarble(message)