document storage and customUtils, and rewrite byline with ES6

browser-version/lib/customUtils.js

@@ -6,6 +6,8 @@
  * Taken from the crypto-browserify module
  * https://github.com/dominictarr/crypto-browserify
  * NOTE: Math.random() does not guarantee "cryptographic quality" but we actually don't need it
+ * @param {number} size in bytes
+ * @return {array<number>}
  */
 const randomBytes = size => {
   const bytes = new Array(size)
@@ -21,6 +23,8 @@ const randomBytes = size => {
 /**
  * Taken from the base64-js module
  * https://github.com/beatgammit/base64-js/
+ * @param {array} uint8
+ * @return {string}
  */
 const byteArrayToBase64 = uint8 => {
   const lookup = 'ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/'
@@ -60,6 +64,8 @@ const byteArrayToBase64 = uint8 => {
  * that's not an issue here
  * The probability of a collision is extremely small (need 3*10^12 documents to have one chance in a million of a collision)
  * See http://en.wikipedia.org/wiki/Birthday_problem
+ * @param {number} len
+ * @return {string}
  */
 const uid = len => byteArrayToBase64(randomBytes(Math.ceil(Math.max(8, len * 2)))).replace(/[+/]/g, '').slice(0, len)
 

lib/byline.js

@@ -21,49 +21,19 @@
 // IN THE SOFTWARE.
 
 const stream = require('stream')
-const util = require('util')
 const timers = require('timers')
 
-// convinience API
-module.exports = function (readStream, options) {
-  return module.exports.createStream(readStream, options)
-}
-
-// basic API
-module.exports.createStream = function (readStream, options) {
-  if (readStream) {
-    return createLineStream(readStream, options)
-  } else {
-    return new LineStream(options)
-  }
-}
-
-// deprecated API
-module.exports.createLineStream = function (readStream) {
-  console.log('WARNING: byline#createLineStream is deprecated and will be removed soon')
-  return createLineStream(readStream)
-}
-
-function createLineStream (readStream, options) {
-  if (!readStream) {
-    throw new Error('expected readStream')
-  }
-  if (!readStream.readable) {
-    throw new Error('readStream must be readable')
-  }
+const createLineStream = (readStream, options) => {
+  if (!readStream) throw new Error('expected readStream')
+  if (!readStream.readable) throw new Error('readStream must be readable')
   const ls = new LineStream(options)
   readStream.pipe(ls)
   return ls
 }
 
-//
-// using the new node v0.10 "streams2" API
-//
-
-module.exports.LineStream = LineStream
-
-function LineStream (options) {
-  stream.Transform.call(this, options)
+class LineStream extends stream.Transform {
+  constructor (options) {
+    super(options)
     options = options || {}
 
     // use objectMode to stop the output from being buffered
@@ -74,19 +44,12 @@ function LineStream (options) {
     this._lastChunkEndedWithCR = false
 
     // take the source's encoding if we don't have one
-  const self = this
-  this.on('pipe', function (src) {
-    if (!self.encoding) {
-      // but we can't do this for old-style streams
-      if (src instanceof stream.Readable) {
-        self.encoding = src._readableState.encoding
-      }
-    }
+    this.once('pipe', src => {
+      if (!this.encoding && src instanceof stream.Readable) this.encoding = src._readableState.encoding // but we can't do this for old-style streams
     })
-}
-util.inherits(LineStream, stream.Transform)
+  }
 
-LineStream.prototype._transform = function (chunk, encoding, done) {
+  _transform (chunk, encoding, done) {
     // decode binary chunks as UTF-8
     encoding = encoding || 'utf8'
 
@@ -94,9 +57,7 @@ LineStream.prototype._transform = function (chunk, encoding, done) {
       if (encoding === 'buffer') {
         chunk = chunk.toString() // utf8
         encoding = 'utf8'
-    } else {
-      chunk = chunk.toString(encoding)
-    }
+      } else chunk = chunk.toString(encoding)
     }
     this._chunkEncoding = encoding
 
@@ -104,9 +65,7 @@ LineStream.prototype._transform = function (chunk, encoding, done) {
     const lines = chunk.split(/\r\n|[\n\v\f\r\x85\u2028\u2029]/g)
 
     // don't split CRLF which spans chunks
-  if (this._lastChunkEndedWithCR && chunk[0] === '\n') {
-    lines.shift()
-  }
+    if (this._lastChunkEndedWithCR && chunk[0] === '\n') lines.shift()
 
     if (this._lineBuffer.length > 0) {
       this._lineBuffer[this._lineBuffer.length - 1] += lines[0]
@@ -116,9 +75,9 @@ LineStream.prototype._transform = function (chunk, encoding, done) {
     this._lastChunkEndedWithCR = chunk[chunk.length - 1] === '\r'
     this._lineBuffer = this._lineBuffer.concat(lines)
     this._pushBuffer(encoding, 1, done)
-}
+  }
 
-LineStream.prototype._pushBuffer = function (encoding, keep, done) {
+  _pushBuffer (encoding, keep, done) {
     // always buffer the last (possibly partial) line
     while (this._lineBuffer.length > keep) {
       const line = this._lineBuffer.shift()
@@ -126,28 +85,29 @@ LineStream.prototype._pushBuffer = function (encoding, keep, done) {
       if (this._keepEmptyLines || line.length > 0) {
         if (!this.push(this._reencode(line, encoding))) {
           // when the high-water mark is reached, defer pushes until the next tick
-        timers.setImmediate(() => {
-          this._pushBuffer(encoding, keep, done)
-        })
+          timers.setImmediate(() => { this._pushBuffer(encoding, keep, done) })
           return
         }
       }
     }
     done()
-}
+  }
 
-LineStream.prototype._flush = function (done) {
+  _flush (done) {
     this._pushBuffer(this._chunkEncoding, 0, done)
-}
+  }
 
-// see Readable::push
-LineStream.prototype._reencode = function (line, chunkEncoding) {
-  if (this.encoding && this.encoding !== chunkEncoding) {
-    return Buffer.from(line, chunkEncoding).toString(this.encoding)
-  } else if (this.encoding) {
-    // this should be the most common case, i.e. we're using an encoded source stream
-    return line
-  } else {
-    return Buffer.from(line, chunkEncoding)
+  // see Readable::push
+  _reencode (line, chunkEncoding) {
+    if (this.encoding && this.encoding !== chunkEncoding) return Buffer.from(line, chunkEncoding).toString(this.encoding)
+    else if (this.encoding) return line // this should be the most common case, i.e. we're using an encoded source stream
+    else return Buffer.from(line, chunkEncoding)
   }
 }
+
+// convenience API
+module.exports = (readStream, options) => module.exports.createStream(readStream, options)
+
+// basic API
+module.exports.createStream = (readStream, options) => readStream ? createLineStream(readStream, options) : new LineStream(options)
+module.exports.LineStream = LineStream

lib/storage.js

@@ -13,9 +13,22 @@ const { callbackify, promisify } = require('util')
 const storage = {}
 const { Readable } = require('stream')
 
+/**
+ * @callback Storage~existsCallback
+ * @param {boolean} exists
+ */
+
+/**
+ * @param {string} file
+ * @param {Storage~existsCallback} cb
+ */
 // eslint-disable-next-line node/no-callback-literal
-storage.exists = (path, cb) => fs.access(path, fs.constants.F_OK, (err) => { cb(!err) })
-storage.existsAsync = path => fsPromises.access(path, fs.constants.F_OK).then(() => true, () => false)
+storage.exists = (file, cb) => fs.access(file, fs.constants.F_OK, (err) => { cb(!err) })
+/**
+ * @param {string} file
+ * @return {Promise<boolean>}
+ */
+storage.existsAsync = file => fsPromises.access(file, fs.constants.F_OK).then(() => true, () => false)
 storage.rename = fs.rename
 storage.renameAsync = fsPromises.rename
 storage.writeFile = fs.writeFile
@@ -32,22 +45,40 @@ storage.mkdir = fs.mkdir
 storage.mkdirAsync = fsPromises.mkdir
 
 /**
- * Explicit name ...
+ * @param {string} file
+ * @return {Promise<void>}
  */
 storage.ensureFileDoesntExistAsync = async file => {
   if (await storage.existsAsync(file)) await storage.unlinkAsync(file)
 }
 
+/**
+ * @callback Storage~errorCallback
+ * @param {?Error} err
+ */
+
+/**
+ * @param {string} file
+ * @param {Storage~errorCallback} callback
+ */
 storage.ensureFileDoesntExist = (file, callback) => callbackify(storage.ensureFileDoesntExistAsync)(file, err => callback(err))
 
 /**
  * Flush data in OS buffer to storage if corresponding option is set
- * @param {String} options.filename
- * @param {Boolean} options.isDir Optional, defaults to false
- * If options is a string, it is assumed that the flush of the file (not dir) called options was requested
+ * @param {object|string} options If options is a string, it is assumed that the flush of the file (not dir) called options was requested
+ * @param {string} [options.filename]
+ * @param {boolean} [options.isDir = false] Optional, defaults to false
+ * @param {Storage~errorCallback} callback
  */
 storage.flushToStorage = (options, callback) => callbackify(storage.flushToStorageAsync)(options, callback)
 
+/**
+ * Flush data in OS buffer to storage if corresponding option is set
+ * @param {object|string} options If options is a string, it is assumed that the flush of the file (not dir) called options was requested
+ * @param {string} [options.filename]
+ * @param {boolean} [options.isDir = false] Optional, defaults to false
+ * @return {Promise<void>}
+ */
 storage.flushToStorageAsync = async (options) => {
   let filename
   let flags
@@ -98,9 +129,9 @@ storage.flushToStorageAsync = async (options) => {
 
 /**
  * Fully write or rewrite the datafile
- * @param {String} filename
- * @param {String[]} lines
- * @param {Function} callback
+ * @param {string} filename
+ * @param {string[]} lines
+ * @param {Storage~errorCallback} callback
  */
 storage.writeFileLines = (filename, lines, callback = () => {}) => {
   try {
@@ -122,19 +153,30 @@ storage.writeFileLines = (filename, lines, callback = () => {}) => {
     callback(err)
   }
 }
-
+/**
+ * Fully write or rewrite the datafile
+ * @param {string} filename
+ * @param {string[]} lines
+ * @return {Promise<void>}
+ * @async
+ */
 storage.writeFileLinesAsync = (filename, lines) => promisify(storage.writeFileLines)(filename, lines)
 
 /**
  * Fully write or rewrite the datafile, immune to crashes during the write operation (data will not be lost)
- * @param {String} filename
- * @param {String[]} lines
- * @param {Function} callback Optional callback, signature: err
+ * @param {string} filename
+ * @param {string[]} lines
+ * @param {Storage~errorCallback} callback Optional callback, signature: err
  */
 storage.crashSafeWriteFileLines = (filename, lines, callback = () => {}) => {
   callbackify(storage.crashSafeWriteFileLinesAsync)(filename, lines, callback)
 }
-
+/**
+ * Fully write or rewrite the datafile, immune to crashes during the write operation (data will not be lost)
+ * @param {string} filename
+ * @param {string[]} lines
+ * @return {Promise<void>}
+ */
 storage.crashSafeWriteFileLinesAsync = async (filename, lines) => {
   const tempFilename = filename + '~'
 
@@ -154,11 +196,16 @@ storage.crashSafeWriteFileLinesAsync = async (filename, lines) => {
 
 /**
  * Ensure the datafile contains all the data, even if there was a crash during a full file write
- * @param {String} filename
- * @param {Function} callback signature: err
+ * @param {string} filename
+ * @param {Storage~errorCallback} callback signature: err
  */
 storage.ensureDatafileIntegrity = (filename, callback) => callbackify(storage.ensureDatafileIntegrityAsync)(filename, callback)
 
+/**
+ * Ensure the datafile contains all the data, even if there was a crash during a full file write
+ * @param {string} filename
+ * @return {Promise<void>}
+ */
 storage.ensureDatafileIntegrityAsync = async filename => {
   const tempFilename = filename + '~'