Add support for time-traveling installs.

doc/misc/npm-config.md

@@ -179,6 +179,22 @@ a non-zero exit code.
 
 What authentication strategy to use with `adduser`/`login`.
 
+### before
+
+* Alias: enjoy-by
+* Default: null
+* Type: Date
+
+If passed to `npm install`, will rebuild the npm tree such that only versions
+that were available **on or before** the `--before` time get installed.
+If there's no versions available for the current set of direct dependencies, the
+command will error.
+
+If the requested version is a `dist-tag` and the given tag does not pass the
+`--before` filter, the most recent version less than or equal to that tag will
+be used. For example, `foo@latest` might install `foo@1.2` even though `latest`
+is `2.0`.
+
 ### bin-links
 
 * Default: `true`

lib/config/defaults.js

@@ -113,6 +113,7 @@ Object.defineProperty(exports, 'defaults', {get: function () {
     'audit-level': 'low',
     'auth-type': 'legacy',
 
+    'before': null,
     'bin-links': true,
     browser: null,
 
@@ -260,6 +261,7 @@ exports.types = {
   audit: Boolean,
   'audit-level': ['low', 'moderate', 'high', 'critical'],
   'auth-type': ['legacy', 'sso', 'saml', 'oauth'],
+  'before': [null, Date],
   'bin-links': Boolean,
   browser: [null, String],
   ca: [null, String, Array],
@@ -394,6 +396,7 @@ function getLocalAddresses () {
 }
 
 exports.shorthands = {
+  before: ['--enjoy-by'],
   s: ['--loglevel', 'silent'],
   d: ['--loglevel', 'info'],
   dd: ['--loglevel', 'verbose'],

lib/install.js

@@ -703,8 +703,25 @@ Installer.prototype.cloneCurrentTreeToIdealTree = function (cb) {
   validate('F', arguments)
   log.silly('install', 'cloneCurrentTreeToIdealTree')
 
-  this.idealTree = copyTree(this.currentTree)
-  this.idealTree.warnings = []
+  if (npm.config.get('before')) {
+    this.idealTree = {
+      package: this.currentTree.package,
+      path: this.currentTree.path,
+      realpath: this.currentTree.realpath,
+      children: [],
+      requires: [],
+      missingDeps: {},
+      missingDevDeps: {},
+      requiredBy: [],
+      error: this.currentTree.error,
+      warnings: [],
+      isTop: true
+    }
+  } else {
+    this.idealTree = copyTree(this.currentTree)
+    this.idealTree.warnings = []
+  }
+
   cb()
 }
 

test/tap/install-before.js

@@ -0,0 +1,89 @@
+'use strict'
+
+const BB = require('bluebird')
+
+const common = require('../common-tap.js')
+const mockTar = require('../util/mock-tarball.js')
+const mr = common.fakeRegistry.compat
+const path = require('path')
+const rimraf = BB.promisify(require('rimraf'))
+const Tacks = require('tacks')
+const { test } = require('tap')
+
+const { Dir, File } = Tacks
+
+const testDir = path.join(__dirname, path.basename(__filename, '.js'))
+
+let server
+test('setup', t => {
+  mr({}, (err, s) => {
+    t.ifError(err, 'registry mocked successfully')
+    server = s
+    t.end()
+  })
+})
+
+test('installs an npm package before a certain date', t => {
+  const fixture = new Tacks(Dir({
+    'package.json': File({})
+  }))
+  fixture.create(testDir)
+  const packument = {
+    name: 'foo',
+    'dist-tags': { latest: '1.2.4' },
+    versions: {
+      '1.2.3': {
+        name: 'foo',
+        version: '1.2.3',
+        dist: {
+          tarball: `${server.registry}/foo/-/foo-1.2.3.tgz`
+        }
+      },
+      '1.2.4': {
+        name: 'foo',
+        version: '1.2.4',
+        dist: {
+          tarball: `${server.registry}/foo/-/foo-1.2.4.tgz`
+        }
+      }
+    },
+    time: {
+      created: '2017-01-01T00:00:01.000Z',
+      modified: '2018-01-01T00:00:01.000Z',
+      '1.2.3': '2017-01-01T00:00:01.000Z',
+      '1.2.4': '2018-01-01T00:00:01.000Z'
+    }
+  }
+  server.get('/foo').reply(200, packument)
+  return mockTar({
+    'package.json': JSON.stringify({
+      name: 'foo',
+      version: '1.2.3'
+    })
+  }).then(tarball => {
+    server.get('/foo/-/foo-1.2.3.tgz').reply(200, tarball)
+    server.get('/foo/-/foo-1.2.4.tgz').reply(500)
+    return common.npm([
+      'install', 'foo',
+      '--before', '2018',
+      '--json',
+      '--cache', path.join(testDir, 'npmcache'),
+      '--registry', server.registry
+    ], { cwd: testDir })
+  }).then(([code, stdout, stderr]) => {
+    t.comment(stdout)
+    t.comment(stderr)
+    t.like(JSON.parse(stdout), {
+      added: [{
+        action: 'add',
+        name: 'foo',
+        version: '1.2.3'
+      }]
+    }, 'installed the 2017 version of the package')
+  })
+})
+
+test('cleanup', t => {
+  server.close()
+  return rimraf(testDir)
+})