feat: Added remove to multistream. (#2257)

Signed-off-by: Paolo Insogna <[email protected]>

Author: ShogunPanda

docs/api.md

@@ -1461,14 +1461,24 @@ Exposes the Pino package version. Also available on the logger instance.
     - Returns: [MultiStreamRes](#multistreamres)
 
  Add `dest` stream to the array of streams of the current instance.
- * `flushSync()`
-   - Returns: `undefined`
+ *  `flushSync()`
+    - Returns: `undefined`
 
  Call `flushSync` on each stream held by the current instance.
+
+ * `lastId`
+   - number
+
+ The ID assigned to the last stream assigned to the current instance.
  * `minLevel`
    - number
 
  The minimum level amongst all the streams held by the current instance.
+
+ * `remove(id)`
+   - `id` [number]
+
+ Removes a stream from the array of streams of the current instance using its assigned ID.
  * `streams`
     - Returns: [StreamEntry[]](#streamentry)
 

lib/multistream.js

@@ -6,7 +6,6 @@ const { DEFAULT_LEVELS } = require('./constants')
 const DEFAULT_INFO_LEVEL = DEFAULT_LEVELS.info
 
 function multistream (streamsArray, opts) {
-  let counter = 0
   streamsArray = streamsArray || []
   opts = opts || { dedupe: false }
 
@@ -21,10 +20,12 @@ function multistream (streamsArray, opts) {
   const res = {
     write,
     add,
+    remove,
     emit,
     flushSync,
     end,
     minLevel: 0,
+    lastId: 0,
     streams: [],
     clone,
     [metadata]: true,
@@ -126,7 +127,7 @@ function multistream (streamsArray, opts) {
       stream: stream_,
       level,
       levelVal: undefined,
-      id: counter++
+      id: ++res.lastId
     }
 
     streams.unshift(dest_)
@@ -137,6 +138,19 @@ function multistream (streamsArray, opts) {
     return res
   }
 
+  function remove (id) {
+    const { streams } = this
+    const index = streams.findIndex(s => s.id === id)
+
+    if (index >= 0) {
+      streams.splice(index, 1)
+      streams.sort(compareByLevel)
+      this.minLevel = streams.length > 0 ? streams[0].level : -1
+    }
+
+    return res
+  }
+
   function end () {
     for (const { stream } of this.streams) {
       if (typeof stream.flushSync === 'function') {
@@ -159,6 +173,7 @@ function multistream (streamsArray, opts) {
     return {
       write,
       add,
+      remove,
       minLevel: level,
       streams,
       clone,

test/multistream.test.js

@@ -570,6 +570,56 @@ test('add a stream', function (t) {
   t.end()
 })
 
+test('remove a stream', function (t) {
+  let messageCount1 = 0
+  let messageCount2 = 0
+  let messageCount3 = 0
+
+  const stream1 = writeStream(function (data, enc, cb) {
+    messageCount1 += 1
+    cb()
+  })
+
+  const stream2 = writeStream(function (data, enc, cb) {
+    messageCount2 += 1
+    cb()
+  })
+
+  const stream3 = writeStream(function (data, enc, cb) {
+    messageCount3 += 1
+    cb()
+  })
+
+  const multi = multistream()
+  const log = pino({ level: 'trace', sync: true }, multi)
+
+  multi.add(stream1)
+  const id1 = multi.lastId
+
+  multi.add(stream2)
+  const id2 = multi.lastId
+
+  multi.add(stream3)
+  const id3 = multi.lastId
+
+  log.info('line')
+  multi.remove(id1)
+
+  log.info('line')
+  multi.remove(id2)
+
+  log.info('line')
+  multi.remove(id3)
+
+  log.info('line')
+  multi.remove(Math.floor(Math.random() * 1000)) // non-existing id
+
+  t.equal(messageCount1, 1)
+  t.equal(messageCount2, 2)
+  t.equal(messageCount3, 3)
+  t.end()
+})
+
 test('multistream.add throws if not a stream', function (t) {
   try {
     pino({