expectjs: update

expect.js.md

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+---
+title: expect.js
+category: Hidden
+redirect_to: /expectjs
+---

expectjs.md

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 ---
 title: expect.js
 category: JavaScript libraries
+layout: 2017/sheet
 ---
 
+### Expectations
+
 ```js
 expect(x).toBe(y)
   .toBe(val)
   .toEqual(val)
   .toThrow(err)
-  .toExist /* aka: toBeTruthy */
-  .toNotExist /* aka: toBeFalsy */
+  .toExist()          // aka: toBeTruthy()
+  .toNotExist()       // aka: toBeFalsy()
   .toBeA(constructor)
   .toBeA('string')
   .toMatch(/expr/)
   .toBeLessThan(n)
   .toBeGreaterThan(n)
-  .toInclude(val) /* aka: toContain */
+  .toBeLessThanOrEqualTo(n)
+  .toBeGreaterThanOrEqualTo(n)
+  .toInclude(val)     // aka: toContain(val)
   .toExclude(val)
-
-/* also: toNotBe, toNotEqual, etc */
+  .toIncludeKey(key)
+  .toExcludeKey(key)
 ```
 
+Also: `toNotBe`, `toNotEqual`, etc for negatives.
+
+### Chaining assertions
+
+```js
+expect(3.14)
+  .toExist()
+  .toBeLessThan(4)
+  .toBeGreaterThan(3)
+```
+
+Assertions can be chained.
+
 ### Spies
 
 ```js
 spy = expect.spyOn(video, 'play')
+```
 
+```js
 spy = expect.spyOn(...)
   .andCallThrough() /* pass through */
   .andCall(fn)
   .andThrow(exception)
   .andReturn(value)
+```
 
+```js
 expect(spy.calls.length).toEqual(1)
 expect(spy.calls[0].context).toBe(video)
 expect(spy.calls[0].arguments).toEqual([ 'some', 'args' ])
 expect(spy.getLastCall().arguments).toEqual(...)
+```
 
+```js
 expect(spy).toHaveBeenCalled()
 expect(spy).toHaveBeenCalledWith('some', 'args')
 ```
 
-https://www.npmjs.com/package/expect
+### References
+
+- <https://www.npmjs.com/package/expect>
+- <https://github.com/mjackson/expect>