Add PackageStats class...

... for computing statistics about a single npm-package

package.json

@@ -27,7 +27,11 @@
     "preversion": "thought --version || npm -g install thought",
     "version": "thoughtful changelog -o -a && npm run thought"
   },
-  "dependencies": {},
+  "dependencies": {
+    "deep-aplus": "^1.0.4",
+    "glob": "^7.1.1",
+    "pify": "^2.3.0"
+  },
   "devDependencies": {
     "chai": "^3.5.0",
     "dirty-chai": "^1.2.2",

src/PackageStats.js

@@ -0,0 +1,82 @@
+const path = require('path')
+const deep = require('deep-aplus')(Promise)
+const pify = require('pify')
+const fs = require('fs')
+const stat = pify(fs.stat)
+const glob = pify(require('glob'))
+
+/**
+ * Computes and aggregates a number of statistics from a package directory
+ * in the node_modules folder
+ *
+ */
+class PackageStats {
+  /**
+   * Create a new PackageStats object
+   * @param {string} directory path to the package-json files
+   * @param {{file: string, stat: fs.Stats}} files files and stats in this package
+   */
+  constructor (directory, files) {
+    /**
+     * @type {string}
+     */
+    this.directory = directory
+    /**
+     * @type {{file: string, stat: fs.Stats}}
+     */
+    this.files = files
+  }
+
+  totalByteSize () {
+    if (!this._totalByteSize) {
+      this._totalByteSize = this.files.reduce((result, file) => result + file.stat.size, 0)
+    }
+    return this._totalByteSize
+  }
+
+  totalBlockSize () {
+    if (!this._totalBlocksize) {
+      this._totalBlockSize = this.files.reduce((result, file) => {
+        return result + Math.ceil(file.stat.size / file.stat.blksize) * file.stat.blksize
+      }, 0)
+    }
+    return this._totalBlockSize
+  }
+
+  /**
+   * Returns a new PackageStats-object with the same directory
+   * and the union of all files in this package and the other packages
+   * @param {PackageStats[]} packages
+   */
+  merge (packages) {
+    var uniq = {}
+    // Merge files
+    this.files.forEach(file => { uniq[file.file] = file })
+    packages.forEach(pkg => {
+      pkg.files.forEach(file => { uniq[file.file] = file })
+    })
+    // Recreate file array
+    var files = Object.keys(uniq).map((key) => uniq[key])
+    return new PackageStats(this.directory, files)
+  }
+
+  /**
+   *
+   * @param packageJsonPath
+   * @return {Promise<PackageStats>}
+   */
+  static loadFrom (packageJsonPath) {
+    var directory = path.dirname(packageJsonPath)
+    return glob('**', {dot: true, cwd: directory, mark: true, ignore: 'node_modules/**'})
+    // Add the directory itself
+      .then(files => ['./'].concat(files))
+      // Gather stats
+      .then(files => files.map(file => ({file: path.join(directory, file), stat: stat(path.join(directory, file))})))
+      // Wait for promises
+      .then(deep)
+      // creaate PackageStats-object
+      .then((files) => new PackageStats(directory, files))
+  }
+}
+
+module.exports = {PackageStats}

test/PackageStats-spec.js

@@ -0,0 +1,65 @@
+/* eslint-env mocha */
+
+const chai = require('chai')
+chai.use(require('dirty-chai'))
+const expect = chai.expect
+const {PackageStats} = require('../src/PackageStats')
+
+describe('The PackageStats-class', function () {
+  it('should load the package-stats from a directory', function () {
+    return PackageStats.loadFrom('test/fixtures/project1/package.json')
+      .then((packageStats) => {
+        expect(packageStats.directory).to.equal('test/fixtures/project1')
+        expect(sortedNameAndSize(packageStats.files)).to.deep.equal([
+          'test/fixtures/project1/ - 4096',
+          'test/fixtures/project1/dir/ - 4096',
+          'test/fixtures/project1/dir/file2.txt - 2',
+          'test/fixtures/project1/file3.txt - 3',
+          'test/fixtures/project1/file5000.txt - 5000',
+          'test/fixtures/project1/file6.txt - 6'
+        ])
+      })
+  })
+
+  it('should compute the byte-size of all the files in a directory', function () {
+    return PackageStats.loadFrom('test/fixtures/project1/package.json')
+      .then((packageStats) => {
+        expect(packageStats.totalByteSize()).to.equal(4096 + 4096 + 2 + 3 + 5000 + 6)
+      })
+  })
+
+  it('should compute the disk usage (by whole blocks) of the directory', function () {
+    return PackageStats.loadFrom('test/fixtures/project1/package.json')
+      .then((packageStats) => {
+        expect(packageStats.totalBlockSize()).to.equal(7 * 4096)
+      })
+  })
+
+  it('should merge two stats-object by unioning the files', function () {
+    return Promise.all([
+      PackageStats.loadFrom('test/fixtures/project1/package.json'),
+      PackageStats.loadFrom('test/fixtures/project2/package.json'),
+      PackageStats.loadFrom('test/fixtures/project1/package.json')
+    ])
+      .then((packages) => {
+        // Merge package with the first package being the main package
+        const merged = packages[0].merge(packages.slice(1))
+        expect(merged, 'Must return a copy').not.to.equal(packages[0])
+        expect(merged.directory).to.equal('test/fixtures/project1')
+        expect(sortedNameAndSize(merged.files)).to.deep.equal([
+          'test/fixtures/project1/ - 4096',
+          'test/fixtures/project1/dir/ - 4096',
+          'test/fixtures/project1/dir/file2.txt - 2',
+          'test/fixtures/project1/file3.txt - 3',
+          'test/fixtures/project1/file5000.txt - 5000',
+          'test/fixtures/project1/file6.txt - 6',
+          'test/fixtures/project2/ - 4096',
+          'test/fixtures/project2/file10.txt - 10'
+        ])
+      })
+  })
+})
+
+function sortedNameAndSize (files) {
+  return files.map((file) => file.file + ' - ' + file.stat.size).sort()
+}

test/fixtures/project1/file3.txt

@@ -0,0 +1 @@
+ab

test/fixtures/project1/file5000.txt

@@ -0,0 +1,100 @@
+0123456789012345678901234567890123456789012345678
+0123456789012345678901234567890123456789012345678
+0123456789012345678901234567890123456789012345678
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+0123456789012345678901234567890123456789012345678

test/fixtures/project1/file6.txt

@@ -0,0 +1 @@
+abcef

test/fixtures/project2/file10.txt

@@ -0,0 +1 @@
+012345678