https://github.com/prestaul/express-json-transform

Express middleware for intercepting and transforming json responses
https://github.com/prestaul/express-json-transform

Last synced: 13 days ago
JSON representation

Express middleware for intercepting and transforming json responses

• Host: GitHub
• URL: https://github.com/prestaul/express-json-transform
• Owner: Prestaul
• License: mit
• Created: 2016-05-01T20:35:13.000Z (over 8 years ago)
• Default Branch: master
• Last Pushed: 2016-05-01T23:16:51.000Z (over 8 years ago)
• Last Synced: 2024-11-06T21:47:10.663Z (2 months ago)
• Language: JavaScript
• Size: 2.93 KB
• Stars: 0
• Watchers: 1
• Forks: 0
• Open Issues: 0
• Metadata Files:
  • Readme: README.md
  • License: LICENSE

Awesome Lists containing this project

README

        
# express-json-transform

Express middleware for intercepting and transforming json responses.

## Installation

```bash

npm i -S express-json-transform

```

## Usage

A transform is passed an object from the response and it returns a replacement.

### Basic usage `jsonTransform( transform )`

Middleware can be created by passing a transform function. The transform function will be called with a response object prior to json serialization and it must return a replacement object.

```js

var express = require('express'),

	jsonTransform = require('express-json-transform');

// Create a transform to remove sensitive data from responses

var cleanJson = jsonTransform(function(json) {

	delete json.sensitiveInfo;

	return json;

});

var app = express();

// The middleware can be used anywhere express accepts middleware

app.use(cleanJson);

```

Now when your route handlers call `res.json({ ... })` or `res.send({ ... })` the objects will be transformed before being sent to the client.

### Conditional usage `jsonTransform( condition, transform )`

Middleware can optionally be created with a function that evaluates whether or not to run the transform. The condition function will be called with a request object and a response object and must return a boolean indicating whether or not the transform should run.

```js

var express = require('express'),

	jsonTransform = require('express-json-transform');

// Create a transform to conditionally remove sensitive data from responses

var cleanJson = jsonTransform(function(req, res) {

    return !!req.params.includeUser;

}, function(json) {

	delete json.sensitiveInfo;

	return json;

});

var app = express();

// The middleware can be used anywhere express accepts middleware

app.use(cleanJson);

```

### Middleware location

Express will let you define middleware in several different places. Each of these uses is valid:

```js

var express = require('express'),

    Router = express.Router;

var transform = require('express-json-transform')(function(json) {

    // modify the response...

    return json;

});

var app = express();

app.use(transform) // application-level middleware

app.get('/path', transform, handler); // middleware for specific route

app.get('/path', [otherMiddleware, transform, handler]) // stacked with other middleware

var router = new Router();

router.use(transform) // router-level middleware

router.get('/path', transform, handler); // middleware for specific route

router.get('/path', [otherMiddleware, transform, handler]) // stacked with other middleware

app.use(router);

```