https://github.com/bttmly/intercept-require
intercept require() calls
https://github.com/bttmly/intercept-require
nodejs require
Last synced: 7 months ago
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intercept require() calls
- Host: GitHub
- URL: https://github.com/bttmly/intercept-require
- Owner: bttmly
- License: mit
- Created: 2015-01-06T23:08:17.000Z (about 11 years ago)
- Default Branch: master
- Last Pushed: 2017-04-14T06:53:28.000Z (almost 9 years ago)
- Last Synced: 2025-04-26T23:31:59.589Z (9 months ago)
- Topics: nodejs, require
- Language: JavaScript
- Homepage:
- Size: 58.6 KB
- Stars: 9
- Watchers: 2
- Forks: 1
- Open Issues: 1
-
Metadata Files:
- Readme: README.md
- License: LICENSE
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README
# intercept-require [](https://travis-ci.org/bttmly/intercept-require)
## Installation
`npm install intercept-require`
## About
Intercept, prevent, modify, and short-circuit calls to `require()`. Given that this involves messing with the methods Node.js uses to require modules, it should be used judiciously. A few possible use-cases:
- You're deprecating use of a library you don't control; use this module to print a deprecation warning and a stack trace whenever that library is `require`'d
- Transparently stubbing dependencies. Sure, dependency injection is probably a better pattern, but it can be verbose. Instead, you could (during testing) replace e.g. `redis` with a simple in-memory store that exposes the same interface.
- Implementing some kind of development environment hot-swapping functionality that wraps modules in a [Proxy](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Proxy) and transparently reloads them when files change
... and any other bad ideas you can think up!
## Example
```js
const intercept = require("intercept-require");
// in this example, just transparently log every require
const restore = intercept(function (moduleExport, info) {
// moduleExport is whatever the actual module exported
// info looks like:
// {
// moduleId: "lodash",
// callingFile: "index.js",
// native: false,
// extname: ".js",
// thirdParty: true,
// exports: [[actual lodash object]]
// absPath: /from/root/to/project/node_modules/lodash/lodash.js,
// absPathResolvedCorrectly: true,
// testOnly: false,
// local: false
// }
console.log("require:", info.moduleId, "from", info.callingFile);
// value returned from this function will be passed back to the caller as if it was module.exports
return moduleExport;
}, config);
// config has only one option `shortCircuit: boolean`
// if short-circuit is active, `moduleExport` argument to listener will be null
// require() calls now being intercepted
restore();
// require() calls no longer intercepted
```