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author | Florian Dold <florian.dold@gmail.com> | 2016-10-10 03:43:44 +0200 |
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committer | Florian Dold <florian.dold@gmail.com> | 2016-10-10 03:43:44 +0200 |
commit | abd94a7f5a50f43c797a11b53549ae48fff667c3 (patch) | |
tree | ab8ed457f65cdd72e13e0571d2975729428f1551 /node_modules/unique-stream/README.md | |
parent | a0247c6a3fd6a09a41a7e35a3441324c4dcb58be (diff) |
add node_modules to address #4364
Diffstat (limited to 'node_modules/unique-stream/README.md')
-rw-r--r-- | node_modules/unique-stream/README.md | 89 |
1 files changed, 89 insertions, 0 deletions
diff --git a/node_modules/unique-stream/README.md b/node_modules/unique-stream/README.md new file mode 100644 index 000000000..f19b20a37 --- /dev/null +++ b/node_modules/unique-stream/README.md @@ -0,0 +1,89 @@ +# unique-stream + +node.js through stream that emits a unique stream of objects based on criteria + +[](http://travis-ci.org/eugeneware/unique-stream) + +## Installation + +Install via npm: + +``` +$ npm install unique-stream +``` + +## Examples + +### Dedupe a ReadStream based on JSON.stringify: + +``` js +var unique = require('unique-stream') + , Stream = require('stream'); + +// return a stream of 3 identical objects +function makeStreamOfObjects() { + var s = new Stream; + s.readable = true; + var count = 3; + for (var i = 0; i < 3; i++) { + setImmediate(function () { + s.emit('data', { name: 'Bob', number: 123 }); + --count && end(); + }); + } + + function end() { + s.emit('end'); + } + + return s; +} + +// Will only print out one object as the rest are dupes. (Uses JSON.stringify) +makeStreamOfObjects() + .pipe(unique()) + .on('data', console.log); + +``` + +### Dedupe a ReadStream based on an object property: + +``` js +// Use name as the key field to dedupe on. Will only print one object +makeStreamOfObjects() + .pipe(unique('name')) + .on('data', console.log); +``` + +### Dedupe a ReadStream based on a custom function: + +``` js +// Use a custom function to dedupe on. Use the 'number' field. Will only print one object. +makeStreamOfObjects() + .pipe(function (data) { + return data.number; + }) + .on('data', console.log); +``` + +## Dedupe multiple streams + +The reason I wrote this was to dedupe multiple object streams: + +``` js +var aggregator = unique(); + +// Stream 1 +makeStreamOfObjects() + .pipe(aggregator); + +// Stream 2 +makeStreamOfObjects() + .pipe(aggregator); + +// Stream 3 +makeStreamOfObjects() + .pipe(aggregator); + +aggregator.on('data', console.log); +``` |