New util extractProperty() and some tests.

src/utils.js

@@ -21,6 +21,15 @@ export const ensureArray = (value) => {
 
 // -------------------------------------------------------------------
 
+// Returns the value of a property and removes it from the object.
+export function extractProperty (obj, prop) {
+  const value = obj[prop]
+  delete obj[prop]
+  return value
+}
+
+// -------------------------------------------------------------------
+
 // Generate a secure random Base64 string.
 export const generateToken = (function (randomBytes) {
   return (n = 32) => randomBytes(n).then(base64url)

src/utils.spec.js

@@ -0,0 +1,49 @@
+/* eslint-env mocha */
+
+import {expect} from 'chai'
+
+// ===================================================================
+
+import {
+  ensureArray,
+  extractProperty
+} from './utils'
+
+// ===================================================================
+
+describe('ensureArray', function () {
+  it('returns an empty array for undefined', function () {
+    expect(ensureArray(undefined)).to.eql([])
+  })
+
+  it('returns the object itself if is already an array', function () {
+    const array = ['foo', 'bar', 'baz']
+
+    expect(ensureArray(array)).to.equal(array)
+  })
+
+  it('wrap the value in an object', function () {
+    const value = {}
+
+    expect(ensureArray(value)).to.includes(value)
+  })
+})
+
+// -------------------------------------------------------------------
+
+describe('extractProperty', function () {
+  it('returns the value of the property', function () {
+    const value = {}
+    const obj = { prop: value }
+
+    expect(extractProperty(obj, 'prop')).to.equal(value)
+  })
+
+  it('removes the property from the object', function () {
+    const value = {}
+    const obj = { prop: value }
+
+    expect(extractProperty(obj, 'prop')).to.equal(value)
+    expect(obj).to.not.have.property('prop')
+  })
+})