brew-tree.js

#!/usr/bin/env node

var _ = require("underscore"),
    async = require("async"),
    exec = require("child_process").exec,
    ProgressBar = require("progress"),
    treeify = require("treeify");

var keep = [];

console.warn("Getting installed packages...");

exec("brew list", function(err, installedPackages) {
  if (err) {
    return console.warn(err);
  }

  installedPackages = installedPackages.trim().split("\n").reduce(function(i, v) {
    i[v] = {
      name: v,
      dependencies: [],
      dependents: [],
    };

    return i;
  }, {});

  console.warn("Got %d installed packages, resolving dependencies...", _.size(installedPackages));

  var bar = new ProgressBar(":bar :percent, :eta seconds left", {
    total: _.size(installedPackages),
    width: 50,
  });

  async.eachLimit(_.toArray(installedPackages), 5, function(installedPackage, done) {
    exec("brew deps " + installedPackage.name, function(err, dependencies) {
      bar.tick();

      if (err) {
        return done(err);
      }

      dependencies = dependencies.trim().split("\n").filter(function(e) {
        return !!e;
      });

      dependencies.forEach(function(dependency) {
        installedPackage.dependencies.push(dependency);

        if (installedPackages[dependency]) {
          installedPackages[dependency].dependents.push(installedPackage.name);
        }
      });

      return done();
    });
  }, function(err) {
    if (err) {
      return console.warn(err);
    }

    console.warn("Done, building dependency tree...");

    var bare = {},
        root = {};

    _.each(installedPackages, function(installedPackage) {
      bare[installedPackage.name] = installedPackage.dependencies.reduce(function(i, v) {
        i[v] = null;
        return i;
      }, {});
    });

    _.each(installedPackages, function(installedPackage) {
      installedPackage.dependencies.forEach(function(k) {
        bare[installedPackage.name][k] = bare[k];
      });
    });

    _.each(installedPackages, function(installedPackage) {
      if (installedPackage.dependents.length === 0) {
        root[installedPackage.name] = bare[installedPackage.name];
      }
    });

    console.log(treeify.asTree(root));

    // populate the array `keep' with the names of packages that you've manually
    // installed, then uncomment this line to get a list of packages that you
    // can safely remove without breaking anything you care about. this is
    // basically ghetto garbage collection with multiple user-initiated passes.
    // console.log(_.difference(_.keys(root), keep).join(" "));
  });
});