mirror of https://github.com/seald/nedb
Merge pull request #5 from eliot-akira/stream-files-by-line
Stream database file line by line to avoid string length limit in Node.jspull/10/head
tex0l
3 years ago
committed by
GitHub
commit
1d8c88842b
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module.exports = {} |
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// Forked from https://github.com/jahewson/node-byline
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// Copyright (C) 2011-2015 John Hewson
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//
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// Permission is hereby granted, free of charge, to any person obtaining a copy
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// of this software and associated documentation files (the "Software"), to
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// deal in the Software without restriction, including without limitation the
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// rights to use, copy, modify, merge, publish, distribute, sublicense, and/or
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// sell copies of the Software, and to permit persons to whom the Software is
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// furnished to do so, subject to the following conditions:
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//
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// The above copyright notice and this permission notice shall be included in
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// all copies or substantial portions of the Software.
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//
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// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
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// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
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// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
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// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
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// FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
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// IN THE SOFTWARE.
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const stream = require('stream') |
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const util = require('util') |
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const timers = require('timers') |
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// convinience API
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module.exports = function (readStream, options) { |
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return module.exports.createStream(readStream, options) |
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} |
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// basic API
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module.exports.createStream = function (readStream, options) { |
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if (readStream) { |
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return createLineStream(readStream, options) |
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} else { |
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return new LineStream(options) |
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} |
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} |
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// deprecated API
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module.exports.createLineStream = function (readStream) { |
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console.log('WARNING: byline#createLineStream is deprecated and will be removed soon') |
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return createLineStream(readStream) |
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} |
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function createLineStream (readStream, options) { |
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if (!readStream) { |
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throw new Error('expected readStream') |
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} |
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if (!readStream.readable) { |
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throw new Error('readStream must be readable') |
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} |
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const ls = new LineStream(options) |
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readStream.pipe(ls) |
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return ls |
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} |
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//
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// using the new node v0.10 "streams2" API
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//
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module.exports.LineStream = LineStream |
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function LineStream (options) { |
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stream.Transform.call(this, options) |
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options = options || {} |
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// use objectMode to stop the output from being buffered
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// which re-concatanates the lines, just without newlines.
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this._readableState.objectMode = true |
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this._lineBuffer = [] |
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this._keepEmptyLines = options.keepEmptyLines || false |
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this._lastChunkEndedWithCR = false |
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// take the source's encoding if we don't have one
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const self = this |
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this.on('pipe', function (src) { |
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if (!self.encoding) { |
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// but we can't do this for old-style streams
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if (src instanceof stream.Readable) { |
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self.encoding = src._readableState.encoding |
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} |
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} |
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}) |
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} |
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util.inherits(LineStream, stream.Transform) |
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LineStream.prototype._transform = function (chunk, encoding, done) { |
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// decode binary chunks as UTF-8
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encoding = encoding || 'utf8' |
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if (Buffer.isBuffer(chunk)) { |
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if (encoding === 'buffer') { |
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chunk = chunk.toString() // utf8
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encoding = 'utf8' |
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} else { |
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chunk = chunk.toString(encoding) |
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} |
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} |
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this._chunkEncoding = encoding |
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// see: http://www.unicode.org/reports/tr18/#Line_Boundaries
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const lines = chunk.split(/\r\n|[\n\v\f\r\x85\u2028\u2029]/g) |
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// don't split CRLF which spans chunks
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if (this._lastChunkEndedWithCR && chunk[0] === '\n') { |
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lines.shift() |
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} |
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if (this._lineBuffer.length > 0) { |
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this._lineBuffer[this._lineBuffer.length - 1] += lines[0] |
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lines.shift() |
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} |
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this._lastChunkEndedWithCR = chunk[chunk.length - 1] === '\r' |
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this._lineBuffer = this._lineBuffer.concat(lines) |
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this._pushBuffer(encoding, 1, done) |
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} |
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LineStream.prototype._pushBuffer = function (encoding, keep, done) { |
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// always buffer the last (possibly partial) line
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while (this._lineBuffer.length > keep) { |
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const line = this._lineBuffer.shift() |
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// skip empty lines
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if (this._keepEmptyLines || line.length > 0) { |
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if (!this.push(this._reencode(line, encoding))) { |
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// when the high-water mark is reached, defer pushes until the next tick
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timers.setImmediate(() => { |
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this._pushBuffer(encoding, keep, done) |
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}) |
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return |
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} |
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} |
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} |
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done() |
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} |
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LineStream.prototype._flush = function (done) { |
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this._pushBuffer(this._chunkEncoding, 0, done) |
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} |
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// see Readable::push
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LineStream.prototype._reencode = function (line, chunkEncoding) { |
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if (this.encoding && this.encoding !== chunkEncoding) { |
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return Buffer.from(line, chunkEncoding).toString(this.encoding) |
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} else if (this.encoding) { |
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// this should be the most common case, i.e. we're using an encoded source stream
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return line |
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} else { |
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return Buffer.from(line, chunkEncoding) |
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} |
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} |
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@ -0,0 +1,207 @@ |
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/* eslint-env mocha */ |
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// Copyright (C) 2013-2015 John Hewson
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//
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// Permission is hereby granted, free of charge, to any person obtaining a copy
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// of this software and associated documentation files (the "Software"), to
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// deal in the Software without restriction, including without limitation the
|
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// rights to use, copy, modify, merge, publish, distribute, sublicense, and/or
|
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// sell copies of the Software, and to permit persons to whom the Software is
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// furnished to do so, subject to the following conditions:
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//
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// The above copyright notice and this permission notice shall be included in
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// all copies or substantial portions of the Software.
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//
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// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
|
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// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
|
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// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
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// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
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// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
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// FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
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// IN THE SOFTWARE.
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const chai = require('chai') |
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const fs = require('fs') |
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const path = require('path') |
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const byline = require('../lib/byline') |
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const { assert } = chai |
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const regEx = /\r\n|[\n\v\f\r\x85\u2028\u2029]/g |
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const localPath = file => path.join(__dirname, 'byline', file) |
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describe('byline', function () { |
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it('should pipe a small file', function (done) { |
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const input = fs.createReadStream(localPath('empty.txt')) |
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const lineStream = byline(input) // convinience API
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const output = fs.createWriteStream(localPath('test.txt')) |
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lineStream.pipe(output) |
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output.on('close', function () { |
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const out = fs.readFileSync(localPath('test.txt'), 'utf8') |
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const in_ = fs.readFileSync(localPath('empty.txt'), 'utf8').replace(/\n/g, '') |
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assert.equal(in_, out) |
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fs.unlinkSync(localPath('test.txt')) |
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done() |
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}) |
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}) |
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it('should work with streams2 API', function (done) { |
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let stream = fs.createReadStream(localPath('empty.txt')) |
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stream = byline.createStream(stream) |
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stream.on('readable', function () { |
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while (stream.read() !== null) { |
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// eslint-ignore-line no-empty
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} |
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}) |
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stream.on('end', function () { |
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done() |
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}) |
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}) |
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it('should ignore empty lines by default', function (done) { |
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const input = fs.createReadStream(localPath('empty.txt')) |
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const lineStream = byline(input) |
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lineStream.setEncoding('utf8') |
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const lines1 = [] |
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lineStream.on('data', function (line) { |
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lines1.push(line) |
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}) |
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lineStream.on('end', function () { |
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let lines2 = fs.readFileSync(localPath('empty.txt'), 'utf8').split(regEx) |
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lines2 = lines2.filter(function (line) { |
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return line.length > 0 |
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}) |
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assert.deepEqual(lines2, lines1) |
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done() |
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}) |
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}) |
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it('should keep empty lines when keepEmptyLines is true', function (done) { |
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const input = fs.createReadStream(localPath('empty.txt')) |
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const lineStream = byline(input, { keepEmptyLines: true }) |
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lineStream.setEncoding('utf8') |
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const lines = [] |
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lineStream.on('data', function (line) { |
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lines.push(line) |
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}) |
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lineStream.on('end', function () { |
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assert.deepEqual(['', '', '', '', '', 'Line 6'], lines) |
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done() |
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}) |
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}) |
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it('should not split a CRLF which spans two chunks', function (done) { |
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const input = fs.createReadStream(localPath('CRLF.txt')) |
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const lineStream = byline(input, { keepEmptyLines: true }) |
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lineStream.setEncoding('utf8') |
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const lines = [] |
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lineStream.on('data', function (line) { |
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lines.push(line) |
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}) |
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lineStream.on('end', function () { |
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assert.equal(2, lines.length) |
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done() |
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}) |
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}) |
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it('should read a large file', function (done) { |
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readFile(localPath('rfc.txt'), done) |
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}) |
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it('should read a huge file', function (done) { |
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// Readable highWaterMark is 16384, so we test a file with more lines than this
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readFile(localPath('rfc_huge.txt'), done) |
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}) |
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function readFile (filename, done) { |
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const input = fs.createReadStream(filename) |
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const lineStream = byline(input) |
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lineStream.setEncoding('utf8') |
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let lines2 = fs.readFileSync(filename, 'utf8').split(regEx) |
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lines2 = lines2.filter(function (line) { |
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return line.length > 0 |
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}) |
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const lines1 = [] |
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let i = 0 |
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lineStream.on('data', function (line) { |
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lines1.push(line) |
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if (line !== lines2[i]) { |
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console.log('EXPECTED:', lines2[i]) |
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console.log(' GOT:', line) |
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assert.fail(null, null, 'difference at line ' + (i + 1)) |
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} |
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i++ |
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}) |
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lineStream.on('end', function () { |
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assert.equal(lines2.length, lines1.length) |
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assert.deepEqual(lines2, lines1) |
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done() |
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}) |
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} |
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it('should handle encodings like fs', function (done) { |
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areStreamsEqualTypes(undefined, function () { |
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areStreamsEqualTypes({ encoding: 'utf8' }, function () { |
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done() |
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}) |
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}) |
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}) |
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it('should pause() and resume() with a huge file', function (done) { |
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const input = fs.createReadStream(localPath('rfc_huge.txt')) |
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const lineStream = byline(input) |
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lineStream.setEncoding('utf8') |
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let lines2 = fs.readFileSync(localPath('rfc_huge.txt'), 'utf8').split(regEx) |
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lines2 = lines2.filter(function (line) { |
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return line.length > 0 |
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}) |
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const lines1 = [] |
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let i = 0 |
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lineStream.on('data', function (line) { |
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lines1.push(line) |
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if (line !== lines2[i]) { |
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console.log('EXPECTED:', lines2[i]) |
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console.log(' GOT:', line) |
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assert.fail(null, null, 'difference at line ' + (i + 1)) |
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} |
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i++ |
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// pause/resume
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lineStream.pause() |
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setImmediate(function () { |
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lineStream.resume() |
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}) |
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}) |
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lineStream.on('end', function () { |
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assert.equal(lines2.length, lines1.length) |
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assert.deepEqual(lines2, lines1) |
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done() |
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}) |
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}) |
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function areStreamsEqualTypes (options, callback) { |
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const fsStream = fs.createReadStream(localPath('empty.txt'), options) |
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const lineStream = byline(fs.createReadStream(localPath('empty.txt'), options)) |
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fsStream.on('data', function (data1) { |
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lineStream.on('data', function (data2) { |
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assert.equal(Buffer.isBuffer(data1), Buffer.isBuffer(data2)) |
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}) |
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lineStream.on('end', function () { |
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callback() |
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}) |
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}) |
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} |
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}) |
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File diff suppressed because one or more lines are too long
@ -0,0 +1,6 @@ |
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Line 6 |
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File diff suppressed because it is too large
Load Diff
File diff suppressed because it is too large
Load Diff
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