CHANGELOG.md

Changelog

This file does not aim to be comprehensive (you have git history for that), rather it lists changes that might impact your own code as a consumer of this library.

2.9.0

New additions

• It is now possible to pass an custom onFinish handler when constructing a Highland Stream from a Node Readable Stream. This allows for special detection of stream completion when necessary. #505. See #490 for a discussion on why this is necessary.

2.8.1

Bugfix

• The Readable stream wrapper changes from 2.8.0 assumed that close would never be emitted before end for any stream. This is not the case for Sockets, which will close when the client disconnects but will end only when it has piped all of its data. For a slow consumer, end may happen after close, causing the Highland stream to drop all data after close is emitted.

  This release fixes the regression at the cost of restoring the old behavior of never ending the Stream when only close is emitted. This does not affect the case where error events are emitted without end. That still works fine. To manually end a stream when it emits close, listen to the event and call stream.end(). Fixes #490.

2.8.0

Bugfix

• A Highland Stream that wraps Readable now properly handles the case where the Readable emits the close event but not the end event (this can happen with an fs read stream when it encounters an error). It will also end the wrapper stream when it encounters an error (this happens when reading from a non-existent file). Before, such streams would simply never end. #479. Fixes #478.

New additions

• toCallback: method for returning the result of a stream to a nodejs-style callback function. #493. Fixes #484.

Improvements

• A Highland Stream that wraps a bluebird promise can now handle bluebird cancellation. When the promise is cancelled the wrapper stream is empty. #487. Fixes #486.

2.7.4

Bugfix

• mergeWithLimit no longer causes an // Unhandled 'error' event error when one of its sources emits an error. #476. Fixes #475.

2.7.3

Bugfix

• pipe now properly unbinds its drain handler from the destination when it is done. Previously, there would have been a memory leak if the destination is long-lived (e.g., as with process.stdout). #466.

2.7.2

Bugfix

• Minor fixes to the documentation.

New additions

• The library's browserify bundle is now published to NPM alongside the regular code. #310. Fixes #309.

2.7.1

Bugfix

• pipe now emits the pipe event to the destination stream. #450. Fixes #449.

New additions

• pipe now takes a second, optional options argument that allows users to decide whether or not to end the destination stream when the source ends. #450.

2.7.0

Broken release. Use 2.7.1 instead.

2.6.0

Bugfix

• parallel no longer drops elements on the floor in a number of cases. #302, #331. Fixes #234, #328.
• Calling next before push within a generator stream no longer causes the stream to resume and throw away data when used with pull. #326. Fixes #325.
• Parallel no longer drops data if paused. #331. Fixes #328.
• Various grammar fixes and documentation updates. #341, #354, #381, #397, #407
• isStream now always returns a boolean. Before, it would return undefined if the argument was an object but not a Highland stream. #343.
• Streams now unpipe from Readable on destroy. #361.
• _send now keeps a reference to the correct consumer/observer array. #367. Fixes #366.
• Streams constructed with pipeline now correctly exert backpressure. #372, #377. Also fixes an possible issue with not consuming errors from promises. #391.
• It is no longer possible to re-enter the consume callback. #393.

New additions

• mergeWithLimit: Like merge, but with an argument to specify the maximum number of parallel stream that can be consumed at once. #375.
• minified build: There is now a minified version of the browser build under dist/highland.min.js. #392.
• wrapCallback: The function now takes a second argument (mappingHint) that describes how arguments passed to the callback are handled. It behaves like the mappingHint parameter of the stream constructor. #247. Fixes #246, #334.
• Node 4 and 5: Added support for node 4 and 5. #383.

Improvements

• The runtime of pick per object is now O(n), where n is the number of properties to be picked. It was previously O(mn), where m is the number of pickable properties on the object. #286.
• Both pick and pickBy can now select non-enumerable keys. #286.
• parallel now throws descriptive errors if it encounters a value that is not a stream. #318.
• The standalone Highland file is now built using Browserify 12.0.1.
• Updates a number of devDependencies. If you develop on Highland, make sure to update the dependencies. #384, #385, #387, #390, #400, #403, #415.
• uniq now uses a Set to compute uniqueness whenever available, resulting in a significant performance boost for large streams. The definition of equality is still ===, not the SameValueZero algorithm used by Set. #395
• parallel now throws if provided an argument that is not a number. #421.

Other

• Dropped support for Node 0.11.
• Dropped support for iojs.
• Deprecation warnings for API changes upcoming in version 3.0.0 have been added. #417

2.5.1

Bugfix

• Move stream check in constructor to beginning of object branch. #303

2.5.0

New additions

• drop: Ignores the first n values of a stream and then emits the rest. #75 #244
• done: Calls the supplied function once the stream has ended. #161
• sort: Collects all values together then emits each value individually but in sorted order. #169 #245
• streamifyAll: Takes an object or a constructor function and returns that object or constructor with streamified versions of its function properties. #226
• Iterator Support: ECMA2015 (aka ES6) style iterators can now be passed to the Highland constructor function. #235
• slice: Creates a new stream with the values from the source in the range of specified in thestart and end parameters. #250
• batchWithTimeOrCount: Takes one Stream and batches incoming data within a maximum time frame into arrays of a maximum length. #284

Improvements

• each now returns an empty stream rather than nothing. #161.
• Ensure through propagates Node stream errors. #240
• Preserve this context of wrapped function when using wrapCallback. #248
• Update tranduce to use latest version of transformer protocol. #261

2.0.0

• The source.merge() algorithm now evaluates the entire source stream before reading from all of the resulting streams in parallel (previously it would start reading as soon as the source emitted the next stream)
• The merge() function now attempts to balance inputs more fairly. For example, if stream A has 100 values buffered and stream B gets a new value after 100ms, if we read at 200ms we'll get a value from each stream. Previously it would exhaust the stream A buffer before reading from stream B.