Incrementally merge directories.

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2.0.06 years ago7 years agoMinified + gzip package size for merge-trees in KB


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Symlink or copy multiple trees of files on top of each other, resulting in a single merged tree.
Optimized for repeated (incremental) merging.


npm install --save merge-trees


  • new MergeTrees(inputPaths, outputPath, options):
* **`inputPaths`**: An array of paths to the input directories

* **`outputPath`**: The path to the output directory. Must exist and be empty.

* **`options`**: A hash of options
  • mergeTrees.merge(): Merge the input directories into the output directory.
Can be called repeatedly for efficient incremental merging.


  • overwrite: By default, node-merge-trees throws an error when a file
exists in multiple nodes. If you pass { overwrite: true }, the output will contain the version of the file as it exists in the last input directory that contains it.
  • annotation: A note to help with logging.


var MergeTrees = require('merge-trees');

var mergeTrees = new MergeTrees(
  ['public', 'scripts'],
  { overwrite: true });

// Recursively symlink all files from the "public" and "scripts"
// directories into the "output-dir" directory.

// ... add or remove files or directories in some input directories ...

// Incrementally update the output directory (efficient).

Say the directory structure is as follows:
├─ public
│  ├─ index.html
│  └─ images
│     └─ logo.png
├─ scripts
│  └─ app.js
├─ output-dir
Running mergeTrees.merge() will generate this folder:
├─ …
└─ output-dir
   ├─ app.js
   ├─ index.html
   └─ images
      └─ logo.png
The parent folders, public and scripts in this case, are not included in the output. The output tree contains only the files within each folder, all mixed together.


Clone this repo and run the tests like so:
npm install
npm test

Issues and pull requests are welcome. If you change code, be sure to re-run npm test. Oftentimes it's useful to add or update tests as well.