feat: added query and header parameter aliasing

README.md

@@ -1,4 +1,7 @@
 [![Commitizen friendly](https://img.shields.io/badge/commitizen-friendly-brightgreen.svg)](http://commitizen.github.io/cz-cli/)
+![release](https://github.com/actions/hello-world/workflows/semantic-release/badge.svg)
 
 # route-param-alias
 Express.js middleware to substitute route parameters with values from other parts of the request.
+
+

index.js

@@ -0,0 +1,72 @@
+const jwt = require('jsonwebtoken')
+
+const getToken = ({ req, tokenLocation, tokenName }) => {
+  if (tokenLocation === 'header') {
+    return req.get(tokenName)
+  } else if (tokenLocation === 'query') {
+    if (!req.query) {
+      throw new Error('No query object found on request object')
+    }
+
+    return req.query[tokenName]
+  }
+}
+
+/**
+ * Get a particular value out of a JWT lying within a Express.js request object
+ * @param {Object} params.req Express.js request object
+ * @param {String} params.tokenLocation property of req where the token is to be found. ex: 'header' or 'query'
+ * @param {String} params.tokenName name of the token property or header
+ * @param {String} params.payloadKey name of the property in the JWT payload
+ * @return value from the JWT
+ */
+const getParamValue = ({ req, tokenLocation, tokenName, payloadKey }) => {
+  const token = getToken({ req, tokenLocation, tokenName })
+  const { [payloadKey]: value } = jwt.decode(token.replace('Bearer ', ''))
+  return value
+}
+
+/**
+ * Allows using route parameter aliases in a request. Aliases are mapped to values
+ * in the payload of a JWT provided elsewhere in the request
+ *
+ * Example:
+ * ```javascript
+ * const routeParamAlias = require('route-param-alias')
+ * const meConverter = routeParamAlias({
+ *  alias: 'me',
+ *  paramName: 'id',
+ *  tokenLocation: 'header',
+ *  tokenName: 'Authorization',
+ *  payloadKey: 'sub'
+ * })
+ *
+ * app.get('/:id', (req, res) => {
+ *  const payload = jwt.decode(req.headers.authorization)
+ *
+ *  /// Assertions before applying middleware
+ *  assert.equals(req.params.id, 'me')
+ *  assert.not.equals(req.params.id, payload.sub)
+ *
+ *  meConverter(req, res, () => {
+ *    /// Assertions after applying middleware
+ *    assert.not.equals(req.params.id, 'me')
+ *    assert.equals(req.params.id, payload.sub)
+ *    ...
+ *  })
+ * })
+ * ```
+ */
+module.exports = ({
+  alias,
+  paramName,
+  tokenLocation = 'header',
+  tokenName = 'Authorization',
+  payloadKey
+}) => (req, _, next) => {
+  if (req.params[paramName] === alias) {
+    req.params[paramName] = getParamValue({ req, tokenLocation, tokenName, payloadKey })
+  }
+
+  next()
+}