1 files changed, 144 insertions, 0 deletions
diff --git a/node_modules/merge2/index.js b/node_modules/merge2/index.js
new file mode 100644
index 0000000..78a61ed
--- /dev/null
+++ b/node_modules/merge2/index.js
@@ -0,0 +1,144 @@
+'use strict'
+/*
+ * merge2
+ * https://github.com/teambition/merge2
+ *
+ * Copyright (c) 2014-2020 Teambition
+ * Licensed under the MIT license.
+ */
+const Stream = require('stream')
+const PassThrough = Stream.PassThrough
+const slice = Array.prototype.slice
+
+module.exports = merge2
+
+function merge2 () {
+  const streamsQueue = []
+  const args = slice.call(arguments)
+  let merging = false
+  let options = args[args.length - 1]
+
+  if (options && !Array.isArray(options) && options.pipe == null) {
+    args.pop()
+  } else {
+    options = {}
+  }
+
+  const doEnd = options.end !== false
+  const doPipeError = options.pipeError === true
+  if (options.objectMode == null) {
+    options.objectMode = true
+  }
+  if (options.highWaterMark == null) {
+    options.highWaterMark = 64 * 1024
+  }
+  const mergedStream = PassThrough(options)
+
+  function addStream () {
+    for (let i = 0, len = arguments.length; i < len; i++) {
+      streamsQueue.push(pauseStreams(arguments[i], options))
+    }
+    mergeStream()
+    return this
+  }
+
+  function mergeStream () {
+    if (merging) {
+      return
+    }
+    merging = true
+
+    let streams = streamsQueue.shift()
+    if (!streams) {
+      process.nextTick(endStream)
+      return
+    }
+    if (!Array.isArray(streams)) {
+      streams = [streams]
+    }
+
+    let pipesCount = streams.length + 1
+
+    function next () {
+      if (--pipesCount > 0) {
+        return
+      }
+      merging = false
+      mergeStream()
+    }
+
+    function pipe (stream) {
+      function onend () {
+        stream.removeListener('merge2UnpipeEnd', onend)
+        stream.removeListener('end', onend)
+        if (doPipeError) {
+          stream.removeListener('error', onerror)
+        }
+        next()
+      }
+      function onerror (err) {
+        mergedStream.emit('error', err)
+      }
+      // skip ended stream
+      if (stream._readableState.endEmitted) {
+        return next()
+      }
+
+      stream.on('merge2UnpipeEnd', onend)
+      stream.on('end', onend)
+
+      if (doPipeError) {
+        stream.on('error', onerror)
+      }
+
+      stream.pipe(mergedStream, { end: false })
+      // compatible for old stream
+      stream.resume()
+    }
+
+    for (let i = 0; i < streams.length; i++) {
+      pipe(streams[i])
+    }
+
+    next()
+  }
+
+  function endStream () {
+    merging = false
+    // emit 'queueDrain' when all streams merged.
+    mergedStream.emit('queueDrain')
+    if (doEnd) {
+      mergedStream.end()
+    }
+  }
+
+  mergedStream.setMaxListeners(0)
+  mergedStream.add = addStream
+  mergedStream.on('unpipe', function (stream) {
+    stream.emit('merge2UnpipeEnd')
+  })
+
+  if (args.length) {
+    addStream.apply(null, args)
+  }
+  return mergedStream
+}
+
+// check and pause streams for pipe.
+function pauseStreams (streams, options) {
+  if (!Array.isArray(streams)) {
+    // Backwards-compat with old-style streams
+    if (!streams._readableState && streams.pipe) {
+      streams = streams.pipe(PassThrough(options))
+    }
+    if (!streams._readableState || !streams.pause || !streams.pipe) {
+      throw new Error('Only readable stream can be merged.')
+    }
+    streams.pause()
+  } else {
+    for (let i = 0, len = streams.length; i < len; i++) {
+      streams[i] = pauseStreams(streams[i], options)
+    }
+  }
+  return streams
+}