expectjs: improve some more

expectjs.md

@@ -2,9 +2,34 @@
 title: expect.js
 category: JavaScript libraries
 layout: 2017/sheet
+updated: 2017-09-02
+weight: -1
 ---
 
-### Expectations
+### Using
+
+```
+npm install --save-dev expect
+```
+{: .-setup}
+
+```js
+// using ES6 modules
+import expect, { createSpy, spyOn, isSpy } from 'expect'
+```
+
+```js
+// using CommonJS modules
+var expect = require('expect')
+var createSpy = expect.createSpy
+var spyOn = expect.spyOn
+var isSpy = expect.isSpy
+```
+
+Expect is a library for assertions in tests.
+See: [mjackson/expect](https://github.com/mjackson/expect)
+
+### Assertions
 
 ```js
 expect(x).toBe(y)
@@ -41,18 +66,27 @@ Assertions can be chained.
 
 ### Spies
 
+```js
+const video = {
+  play: function () { ··· }
+}
+```
+{: .-setup}
+
 ```js
 spy = expect.spyOn(video, 'play')
 ```
 
 ```js
-spy = expect.spyOn(...)
+spy = expect.spyOn(···)
-  .andCallThrough() /* pass through */
+  .andCallThrough()      // pass through
   .andCall(fn)
   .andThrow(exception)
   .andReturn(value)
 ```
 
+### Assertions on spies
+
 ```js
 expect(spy.calls.length).toEqual(1)
 expect(spy.calls[0].context).toBe(video)