import-in-the-middle - npm Package Compare versions

Comparing version 1.0.1 to 1.1.0

index.d.ts

@@ -6,12 +6,70 @@ // Unless explicitly stated otherwise all files in this repository are licensed under the Apache 2.0 License.
 /**
+ * Property bag representing a module's exports, including the `default` if
+ * present.
+ */
+export type Namespace = { [key: string]: any }
+
+/**
  * A hook function to be run against loaded modules.
+ * Not to be confused with `HookFunction`, used by the lower-level API.
+ * @param {exported} { [string]: any } An object representing the exported
+ * items of a module.
+ * @param {name} string The name of the module. If it is (or is part of) a
+ * package in a node_modules directory, this will be the path of the file
+ * starting from the package name.
+ * @param {baseDir} string The absolute path of the module, if not provided in
+ * `name`.
+ * @return any A value that can will be assigned to `exports.default`. This is
+ * equivalent to doing that assignment in the body of this function.
+ */
+export type HookFn = (exported: Namespace, name: string, baseDir: string|void) => any
+
+export type Options = {
+  internals?: boolean
+}
+
+declare class Hook {
+  /**
+   * Creates a hook to be run on any already loaded modules and any that will
+   * be loaded in the future. It will be run once per loaded module. If
+   * statically imported, any variables bound directly to exported items will
+   * be re-bound if those items are re-assigned in the hook function.
+   * @param {Array<string>} [modules] A list of modules to run this hook on. If
+   * omitted, it will run on every import everywhere.
+   * @param {Options} [options] An options object. If omitted, the default is
+   * `{ internals: false }`. If internals is true, then the hook will operate
+   * on internal modules of packages in node_modules. Otherwise it will not,
+   * unless they are mentioned specifically in the modules array.
+   * @param {HookFunction} hookFn The function to be run on each module.
+   */
+  constructor (modules: Array<string>, options: Options, hookFn: HookFn)
+  constructor (modules: Array<string>, hookFn: HookFn)
+  constructor (hookFn: HookFn)
+
+  /**
+   * Disables this hook. It will no longer be run against any subsequently
+   * loaded modules.
+   */
+  unhook(): void
+}
+
+export default Hook
+
+/**
+ * A hook function to be run against loaded modules. To be used with the
+ * lower-level APIs `addHook` and `removeHook`.
  * @param {url} string The absolute path of the module, as a `file:` URL string.
- * @param {exported} { [string]: any } An object representing the exported items of a module.
+ * @param {exported} { [string]: any } An object representing the exported
+ * items of a module.
  */
-export type HookFunction = (url: string, exported: { [string]: any }) => void
+export type HookFunction = (url: string, exported: Namespace) => void
 
 /**
- * Adds a hook to be run on any already loaded modules and any that will be loaded in the future.
- * It will be run once per loaded module. If statically imported, any variables bound directly to
- * exported items will be re-bound if those items are re-assigned in the hook.
+ * Adds a hook to be run on any already loaded modules and any that will be
+ * loaded in the future.  It will be run once per loaded module. If statically
+ * imported, any variables bound directly to exported items will be re-bound if
+ * those items are re-assigned in the hook.
+ *
+ * This is the lower-level API for hook creation. It will be run on every
+ * single imported module, rather than with any filtering.
  * @param {HookFunction} hookFn The function to be run on each module.
@@ -22,6 +80,9 @@ */
 /**
- * Removes a hook that has been previously added with `addHook`. It will no longer be run against
- * any subsequently loaded modules.
+ * Removes a hook that has been previously added with `addHook`. It will no
+ * longer be run against any subsequently loaded modules.
+ *
+ * This is the lower-level API for hook removal, and cannot be used with the
+ * `Hook` class.
  * @param {HookFunction} hookFn The function to be removed.
  */
 export declare function removeHook(hookFn: HookFunction): void

index.js

@@ -5,22 +5,13 @@ // Unless explicitly stated otherwise all files in this repository are licensed under the Apache 2.0 License.
 
-const importHooks = [] // TODO should this be a Set?
+const path = require('path')
+const parse = require('module-details-from-path')
+const { fileURLToPath } = require('url')
 
-const setters = new WeakMap()
+const {
+  importHooks,
+  specifiers,
+  toHook
+} = require('./lib/register')
 
-const toHook = []
-
-const proxyHandler = {
-  set(target, name, value) {
-    return setters.get(target)[name](value)
-  }
-}
-
-exports._register =  function _register(name, namespace, set) {
-  setters.set(namespace, set)
-  const proxy = new Proxy(namespace, proxyHandler)
-  importHooks.forEach(hook => hook(name, proxy))
-  toHook.push([name, proxy])
-}
-
-exports.addHook = function addHook(hook) {
+function addHook(hook) {
   importHooks.push(hook)
@@ -30,3 +21,3 @@ toHook.forEach(([name, namespace]) => hook(name, namespace))
 
-exports.removeHook = function removeHook(hook) {
+function removeHook(hook) {
   const index = importHooks.indexOf(hook)
@@ -37,1 +28,65 @@ if (index > -1) {
 }
+
+function callHookFn(hookFn, namespace, name, baseDir) {
+  const newDefault = hookFn(namespace, name, baseDir)
+  if (newDefault && newDefault !== namespace) {
+    namespace.default = newDefault
+  }
+}
+
+function Hook(modules, options, hookFn) {
+  if ((this instanceof Hook) === false) return new Hook(modules, options, hookFn)
+  if (typeof modules === 'function') {
+    hookFn = modules
+    modules = null
+    options = null
+  } else if (typeof options === 'function') {
+    hookFn = options
+    options = null
+  }
+  const internals = options ? options.internals === true : false
+
+  this._iitmHook = (name, namespace) => {
+    const filename = name
+    const isBuiltin = name.startsWith('node:')
+    let baseDir
+
+    if (isBuiltin) {
+      name = name.replace(/^node:/, '')
+    } else {
+      name = name.replace(/^file:\/\//, '')
+      const details = parse(name)
+      if (details) {
+        name = details.name
+        baseDir = details.basedir
+      }
+    }
+
+    if (modules) {
+      for (const moduleName of modules) {
+        if (moduleName === name) {
+          if (baseDir) {
+            if (internals) {
+              name = name + path.sep + path.relative(baseDir, fileURLToPath(filename))
+            } else {
+              if (!baseDir.endsWith(specifiers.get(filename))) continue
+            }
+          }
+          callHookFn(hookFn, namespace, name, baseDir)
+        }
+      }
+    } else {
+      callHookFn(hookFn, namespace, name, baseDir)
+    }
+  }
+
+  addHook(this._iitmHook)
+}
+
+Hook.prototype.unhook = function () {
+  removeHook(this._iitmHook)
+}
+
+module.exports = Hook
+module.exports.addHook = addHook
+module.exports.removeHook = removeHook

package.json

 {
   "name": "import-in-the-middle",
-  "version": "1.0.1",
+  "version": "1.1.0",
   "description": "Intercept imports in Node.js",
   "main": "index.js",
   "scripts": {
-    "test": "c8 --check-coverage --lines 100 imhotap --runner test/runtest --files test/*.*js"
+    "test": "c8 --check-coverage --lines 100 imhotap --runner test/runtest --files test/{hook,low-level}/*.*js",
+    "coverage": "c8 --reporter html imhotap --runner test/runtest --files test/{hook,low-level}/*.*js && echo '\nNow open coverage/index.html\n'"
   },
@@ -30,3 +31,6 @@ "repository": {
     "imhotap": "^1.1.0"
+  },
+  "dependencies": {
+    "module-details-from-path": "^1.0.3"
   }
 }

README.md

@@ -10,3 +10,7 @@ # import-in-the-middle
 
-See the Typescript definition file for API docs.
+The API for
+`require-in-the-middle` is followed as closely as possible as the default
+export. There are lower-level `addHook` and `removeHook` exports available which
+don't do any filtering of modules, and present the full file URL as a parameter
+to the hook. See the Typescript definition file for detailed API docs.
 
@@ -18,12 +22,10 @@ You can modify anything exported from any given ESM or CJS module that's
 ```js
-import { addHook } from 'import-in-the-middle'
-import { foo } from './module-i-want-to-modify.mjs'
+import Hook from 'import-in-the-middle'
+import { foo } from 'package-i-want-to-modify'
 
 console.log(foo) // whatever that module exported
 
-addHook((url, exported) => {
+Hook(['package-i-want-to-modify'], (exported, name, baseDir) => {
   // `exported` is effectively `import * as exported from ${url}`
-  if (url.match(/module-i-want-to-modify.mjs$/)) {
-    exported.foo += 1
-  }
+  exported.foo += 1
 })
@@ -38,3 +40,3 @@
 ```
---loader=/path/to/import-in-the-middle/hook.mjs
+--loader=import-in-the-middle/hook.mjs
 ```
@@ -41,0 +43,0 @@

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Major refactor

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Package has recently undergone a major refactor. It may be unstable or indicate significant internal changes. Use caution when updating to versions that include significant changes.

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Debug access

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Uses debug, reflection and dynamic code execution features.

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Fixed alerts

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Improved metrics

Total package byte prevSize

25497

increased by89.09%

Number of package files

32

increased by60%

Lines of code

561

increased by115.77%

Number of lines in readme file

47

increased by4.44%

Worsened metrics

Dependency count

1

increased byInfinity%

Number of low supply chain risk alerts

1

increased byInfinity%

Number of medium supply chain risk alerts

1

increased byInfinity%

Dependency changes

• + Addedmodule-details-from-path@^1.0.3

• + Addedmodule-details-from-path@1.0.3(transitive)