feat: require hooks from pnpmfile.js

Ref #861

README.md

@@ -27,6 +27,7 @@ Like this project? Let people know with a [tweet](https://bit.ly/tweet-pnpm).
 * [Install](#install)
 * [Usage](#usage)
   * [Configuring](#configuring)
+  * [Hooks](#hooks)
 * [Benchmark](#benchmark)
 * [Limitations](#limitations)
 * [Frequently Asked Questions](#frequently-asked-questions)
@@ -144,6 +145,32 @@ that rely on location but gives an average of **8% installation speed improvemen
 
 If false, doesn't check whether packages in the store were mutated.
 
+### Hooks
+
+pnpm allows to step directly into the installation process via special functions called *hooks*.
+Hooks can be declared in a file called `pnpmfile.js`. `pnpmfile.js` should live in the root of the project.
+
+An example of a `pnpmfile.js` that changes the dependencies field of a dependency:
+
+```js
+module.exports = {
+  hooks: {
+    readPackage
+  }
+}
+
+// This hook will override the manifest of foo@1 after downloading it from the registry
+// foo@1 will always be installed with the second version of bar
+function readPackage (pkg) {
+  if (pkg.name === 'foo' && pkg.version.startsWith('1.')) {
+    pkg.dependencies = {
+      bar: '^2.0.0'
+    }
+  }
+  return pkg
+}
+```
+
 ## Benchmark
 
 pnpm is faster than npm and Yarn. See [this](https://github.com/zkochan/node-package-manager-benchmark)

package.json

@@ -38,7 +38,7 @@
     "pnpm-list": "^1.0.0",
     "pnpm-logger": "^0.5.4",
     "ramda": "^0.24.1",
-    "supi": "^0.2.16",
+    "supi": "^0.2.17",
     "update-notifier": "^2.1.0"
   },
   "devDependencies": {

shrinkwrap.yaml

@@ -24,7 +24,7 @@ dependencies:
   pnpm-logger: 0.5.4
   ramda: 0.24.1
   rimraf: 2.6.1
-  supi: 0.2.16
+  supi: 0.2.17
   update-notifier: 2.2.0
 devDependencies:
   '@types/mkdirp': 0.5.1
@@ -2234,7 +2234,7 @@ packages:
   /strip-json-comments/2.0.1:
     resolution:
       integrity: sha1-PFMZQukIwml8DsNEhYwobHygpgo=
-  /supi/0.2.16:
+  /supi/0.2.17:
     dependencies:
       '@types/byline': 4.2.31
       '@types/common-tags': 1.2.5
@@ -2292,7 +2292,7 @@ packages:
       write-pkg: 3.1.0
       write-yaml-file: 1.0.0
     resolution:
-      integrity: sha512-BKYNiwcn9LeMczysq2CoyDK1IWNBD+ar0oFDZ3hHZSu70jjNyQaErz09FzELvXH1cc29Ekm5i/SL8PSmp+dNjA==
+      integrity: sha512-vnfuOLiCHw4XxhG6fnyxo2oF/ly0U9LT/+y8d0IDSA+eukJGw6AhUsVEZhFdXh07txMRK2QFSMGFT4622YMYew==
   /supports-color/2.0.0:
     resolution:
       integrity: sha1-U10EXOa2Nj+kARcIRimZXp3zJMc=
@@ -2609,7 +2609,7 @@ specifiers:
   pnpm-logger: ^0.5.4
   ramda: ^0.24.1
   rimraf: ^2.5.4
-  supi: ^0.2.16
+  supi: ^0.2.17
   tslint: ^5.4.2
   typescript: ^2.4.1
   update-notifier: ^2.1.0

src/cmd/install.ts

@@ -1,4 +1,6 @@
 import {install, installPkgs, PnpmOptions} from 'supi'
+import path = require('path')
+import logger from 'pnpm-logger'
 
 /**
  * Perform installation.
@@ -9,8 +11,30 @@ export default function installCmd (input: string[], opts: PnpmOptions) {
   // `pnpm install ""` is going to be just `pnpm install`
   input = input.filter(Boolean)
 
+  const prefix = opts.prefix || process.cwd()
+  opts['hooks'] = requireHooks(prefix)
+
   if (!input || !input.length) {
     return install(opts)
   }
   return installPkgs(input, opts)
 }
+
+function requireHooks (prefix: string) {
+  try {
+    const pnpmFilePath = path.join(prefix, 'pnpmfile.js')
+    const pnpmFile = require(pnpmFilePath)
+    const hooks = pnpmFile && pnpmFile.hooks
+    if (!hooks) return {}
+    if (hooks.readPackage) {
+      if (typeof hooks.readPackage !== 'function') {
+        throw new TypeError('hooks.readPackage should be a function')
+      }
+      logger.info('readPackage hook is declared. Manifests of dependencies might get overridden')
+    }
+    return hooks
+  } catch (err) {
+    if (err['code'] !== 'MODULE_NOT_FOUND') throw err
+    return {}
+  }
+}

test/install/hooks.ts

@@ -0,0 +1,35 @@
+import tape = require('tape')
+import promisifyTape from 'tape-promise'
+import {
+  prepare,
+  addDistTag,
+  execPnpm
+} from '../utils'
+import fs = require('mz/fs')
+
+const test = promisifyTape(tape)
+
+test('readPackage hook', async (t: tape.Test) => {
+  const project = prepare(t)
+
+  await fs.writeFile('pnpmfile.js', `
+    'use strict'
+    module.exports = {
+      hooks: {
+        readPackage (pkg) {
+          if (pkg.name === 'pkg-with-1-dep') {
+            pkg.dependencies['dep-of-pkg-with-1-dep'] = '100.0.0'
+          }
+          return pkg
+        }
+      }
+    }
+  `, 'utf8')
+
+  // w/o the hook, 100.1.0 would be installed
+  await addDistTag('dep-of-pkg-with-1-dep', '100.1.0', 'latest')
+
+  await execPnpm('install', 'pkg-with-1-dep')
+
+  await project.storeHas('dep-of-pkg-with-1-dep', '100.0.0')
+})

test/install/index.ts

@@ -1,2 +1,3 @@
 import './misc'
 import './lifecycleScripts'
+import './hooks'