npm:bdwain-folder-hash

README

Create a hash checksum over a folder or a file.
The hashes are propagated upwards, the hash that is returned for a folder is generated over all the hashes of its children.
The hashes are generated with the sha1 algorithm and returned in base64 encoding by default.

Each file returns a name and a hash, and each folder returns additionally an array of children (file or folder elements).

Usage

First, install folder-hash with npm install --save folder-hash or yarn add folder-hash.

Simple example

To see differences to the last version of this package, I would create hashes over all .js and .json files. But ignore everything inside folders starting wiht a dot, and also from the folders node_modules, test_coverage. The structure of the options object is documented on this page.
This example is also stored in ./examples/readme-example1.js.

const { hashElement } = require('folder-hash');

const options = {
    folders: { exclude: ['.*', 'node_modules', 'test_coverage'] },
    files: { include: ['*.js', '*.json'] }
};

console.log('Creating a hash over the current folder:');
hashElement('.', options)
    .then(hash => {
        console.log(hash.toString());
    })
    .catch(error => {
        return console.error('hashing failed:', error);
    });

The returned information looks for example like this:

Creating a hash over the current folder:
{ name: '.', hash: 'YZOrKDx9LCLd8X39PoFTflXGpRU=,'
  children: [
    { name: 'examples', hash: 'aG8wg8np5SGddTnw1ex74PC9EnM=,'
      children: [
        { name: 'readme-example1.js', hash: 'Xlw8S2iomJWbxOJmmDBnKcauyQ8=' }
        { name: 'readme-with-callbacks.js', hash: 'ybvTHLCQBvWHeKZtGYZK7+6VPUw=' }
        { name: 'readme-with-promises.js', hash: '43i9tE0kSFyJYd9J2O0nkKC+tmI=' }
        { name: 'sample.js', hash: 'PRTD9nsZw3l73O/w5B2FH2qniFk=' }
      ]}
    { name: 'index.js', hash: 'kQQWXdgKuGfBf7ND3rxjThTLVNA=' }
    { name: 'package.json', hash: 'w7F0S11l6VefDknvmIy8jmKx+Ng=' }
    { name: 'test', hash: 'H5x0JDoV7dEGxI65e8IsencDZ1A=,'
      children: [
        { name: 'parameters.js', hash: '3gCEobqzHGzQiHmCDe5yX8weq7M=' }
        { name: 'test.js', hash: 'kg7p8lbaVf1CPtWLAIvkHkdu1oo=' }
      ]}
  ]}

And the structure may be traversed to e.g. create incremental backups.

It is also possible to only match the full path and not the basename. The same configuration could look like this:
You should be aware that *nix and Windows behave differently, so please use caution.

const options = {
    folders: {
        exclude: ['.*', '**.*', '**node_modules', '**test_coverage'],
        matchBasename: false, matchPath: true
    },
    files: {
        //include: ['**.js', '**.json' ], // Windows
        include: ['*.js', '**/*.js', '*.json', '**/*.json'], // *nix
        matchBasename: false, matchPath: true
    }
};

Parameters for the hashElement function

Name	Type	Attributes	Description
name	string		element name or an element's path
dir	string	<optional>	directory that contains the element (generated from name if omitted)
options	Object	<optional>	Options object (see below)
callback	fn	<optional>	Error-first callback function

Options

Default values

{
    algo: 'sha1',       // see crypto.getHashes() for options
    encoding: 'base64', // 'base64', 'hex' or 'binary'
    files: {
        exclude: [],
        include: [],
        matchBasename: true,
        matchPath: false,
        ignoreBasename: false,
        ignoreRootName: false
    },
    folders: {
        exclude: [],
        include: [],
        matchBasename: true,
        matchPath: false,
        ignoreRootName: false
    }
}

Name	Type	Attributes	Default	Description
algo	string	<optional>	'sha1'	checksum algorithm, see options in crypto.getHashes()
encoding	string	<optional>	'base64'	encoding of the resulting hash. One of 'base64', 'hex' or 'binary'
files	Object	<optional>	Rules object (see below)
folders	Object	<optional>	Rules object (see below)

Rules object properties

Name	Type	Attributes	Default	Description
exclude	Array.<string> \|\| Function	<optional>	[]	Array of optional exclude glob patterns, see minimatch doc. Can also be a function which returns true if the passed file is excluded.
include	Array.<string> \|\| Function	<optional>	[]	Array of optional include glob patterns, see minimatch doc. Can also be a function which returns true if the passed file is included.
matchBasename	bool	<optional>	true	Match the glob patterns to the file/folder name
matchPath	bool	<optional>	false	Match the glob patterns to the file/folder path
ignoreBasename	bool	<optional>	false	Set to true to calculate the hash without the basename element
ignoreRootName	bool	<optional>	false	Set to true to calculate the hash without the basename of the root (first) element

Examples

Other examples using promises

See file ./examples/readme-with-promises.js

const path = require('path');
const { hashElement } = require('folder-hash');

// pass element name and folder path separately
hashElement('test', path.join(__dirname, '..'))
  .then(hash => {
    console.log('Result for folder "../test":', hash.toString(), '\n');
  })
  .catch(error => {
    return console.error('hashing failed:', error);
  });

// pass element path directly
hashElement(__dirname)
  .then(hash => {
    console.log(`Result for folder "${__dirname}":`);
    console.log(hash.toString(), '\n');
  })
  .catch(error => {
    return console.error('hashing failed:', error);
  });

// pass options (example: exclude dotFolders)
const options = { encoding: 'hex', folders: { exclude: ['.*'] } };
hashElement(__dirname, options)
  .then(hash => {
    console.log('Result for folder "' + __dirname + '" (with options):');
    console.log(hash.toString(), '\n');
  })
  .catch(error => {
    return console.error('hashing failed:', error);
  });

Other examples using error-first callbacks

See ./examples/readme-with-callbacks.js

const path = require('path');
const { hashElement } = require('folder-hash');

// pass element name and folder path separately
hashElement('test', path.join(__dirname, '..'), (error, hash) => {
    if (error) {
        return console.error('hashing failed:', error);
    } else {
        console.log('Result for folder "../test":', hash.toString(), '\n');
    }
});

// pass element path directly
hashElement(__dirname, (error, hash) => {
    if (error) {
        return console.error('hashing failed:', error);
    } else {
        console.log('Result for folder "' + __dirname + '":');
        console.log(hash.toString(), '\n');
    }
});

// pass options (example: exclude dotFiles)
const options = { algo: 'md5', files: { exclude: ['.*'], matchBasename: true } };
hashElement(__dirname, options, (error, hash) => {
    if (error) {
        return console.error('hashing failed:', error);
    } else {
        console.log('Result for folder "' + __dirname + '":');
        console.log(hash.toString());
    }
});

Behavior

The behavior is documented and verified in the unit tests. Execute npm test or mocha test, and have a look at the test subfolder.
You can also have a look at the CircleCI report.

Creating hashes over files (with default options)

The hashes are the same if:

A file is checked again
Two files have the same name and content (but exist in different folders)

The hashes are different if:

A file was renamed or its content was changed
Two files have the same name but different content
Two files have the same content but different names

Creating hashes over folders (with default options)

Content means in this case a folder's children - both the files and the subfolders with their children.