|
| 1 | +// first do: |
| 2 | +// curl -s http://www.gutenberg.org/cache/epub/2701/pg2701.txt > mobydick.txt |
| 3 | + |
| 4 | +var fs = require('fs'); |
| 5 | +var path = require('path'); |
| 6 | +var through = require('through2'); |
| 7 | +var combine = require('stream-combiner2') |
| 8 | +var split = require('split'); |
| 9 | + |
| 10 | +read('mobydick.txt') |
| 11 | + .pipe(replace(/\s+/g, '\n')) |
| 12 | + .pipe(filter(/whale/i)) |
| 13 | + .pipe(linecount(function (count) { |
| 14 | + console.log(count) |
| 15 | + })) |
| 16 | +; |
| 17 | + |
| 18 | +function read (file) { |
| 19 | + return fs.createReadStream(path.join(__dirname, file)); |
| 20 | +} |
| 21 | + |
| 22 | +function replace (pattern, replacement) { |
| 23 | + return combine(split(), through(function (buf, enc, next) { |
| 24 | + var line = buf.toString('utf8'); |
| 25 | + this.push(line.replace(pattern, replacement) + '\n'); |
| 26 | + next(); |
| 27 | + })); |
| 28 | +} |
| 29 | + |
| 30 | +function filter (pattern) { |
| 31 | + return combine(split(), through(function (buf, enc, next) { |
| 32 | + var line = buf.toString('utf8'); |
| 33 | + if (pattern.test(line)) this.push(line + '\n'); |
| 34 | + next(); |
| 35 | + })); |
| 36 | +} |
| 37 | + |
| 38 | +function linecount (cb) { |
| 39 | + var count = 0; |
| 40 | + return combine(split(), through(write, end)); |
| 41 | + function write (buf, enc, next) { count ++; next() } |
| 42 | + function end () { cb(count) } |
| 43 | +} |
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