Split2(matcher, mapper, options)#
Break up a stream and reassemble it so that each line is a chunk.split2 is inspired by @dominictarr split module,
and it is totally API compatible with it.
However, it is based on Node.js core Transform.
matcher may be a String, or a RegExp. Example, read every line in a file ...
fs.createReadStream(file)
.pipe(split2())
.on('data', function (line) {
//each chunk now is a separate line!
})
split takes the same arguments as string.split except it defaults to '/\r?\n/', and the optional limit paremeter is ignored.
String#split
split takes an optional options object on it's third argument, which
is directly passed as a
Transform
option.
Additionally, the .maxLength and .skipOverflow options are implemented, which set limits on the internal
buffer size and the stream's behavior when the limit is exceeded. There is no limit unless maxLength is set. When
the internal buffer size exceeds maxLength, the stream emits an error by default. You may also set skipOverflow to
true to suppress the error and instead skip past any lines that cause the internal buffer to exceed maxLength.
Calling .destroy will make the stream emit close. Use this to perform cleanup logic
var splitFile = function(filename) {
var file = fs.createReadStream(filename)
return file
.pipe(split2())
.on('close', function() {
// destroy the file stream in case the split stream was destroyed
file.destroy()
})
}
var stream = splitFile('my-file.txt')
stream.destroy() // will destroy the input file streamNDJ - Newline Delimited Json#
split2 accepts a function which transforms each line.
fs.createReadStream(file)
.pipe(split2(JSON.parse))
.on('data', function (obj) {
//each chunk now is a js object
})
.on("error", function(error) => {
//handling parsing errors
})However, in @dominictarr split the mapper
is wrapped in a try-catch, while here it is not: if your parsing logic can throw, wrap it yourself. Otherwise, you can also use the stream error handling when mapper function throw.
License#
Copyright (c) 2014-2021, Matteo Collina [email protected]
Permission to use, copy, modify, and/or distribute this software for any
purpose with or without fee is hereby granted, provided that the above
copyright notice and this permission notice appear in all copies.
THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR
IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.