Merge branch 'master' into before-after-generate

docs/api/derived.md

@@ -21,7 +21,7 @@ To have more control over your computed values, you can use the `derived` functi
 ### Example
 
 ```js
-import { createSpec, faker } from '@helpscout/helix'
+import { createSpec, derived, faker } from '@helpscout/helix'
 
 const Spec = createSpec({
   fname: faker.name.firstName(), // Alice

package.json

@@ -1,7 +1,7 @@
 {
   "name": "@helpscout/helix",
   "private": false,
-  "version": "0.0.11",
+  "version": "0.0.12",
   "description": "A Faker-powered fixture generator for Javascript",
   "main": "lib/index.js",
   "module": "lib/index.es.js",

src/HelixSpec/index.js

@@ -41,8 +41,8 @@ class HelixSpec {
     return this
   }
 
-  generate (count = 0, max) {
-    if (!isNumber(count)) {
+  generate (count, max) {
+    if (!isNumber(count) && count !== undefined) {
       throw Exception('HelixSpec.generate()', 'Argument must be a valid number.')
     }
     if (max !== undefined) {
@@ -55,8 +55,7 @@ class HelixSpec {
       count = faker.random.number({min: count, max})
     }
 
-    // If count was 0, max was specified, but the randomized count comes back 0, return []
-    const isArray = count || max !== undefined
+    const isArray = isNumber(count)
     const generatedSpecs = isArray
       ? [...Array(count)].map(() => {
         // Respect seed value for multi-generated specs

src/HelixSpec/tests/generate.test.js

@@ -48,10 +48,10 @@ test('Throw if max argument is less than count argument', () => {
 })
 
 test('Generates fixtures from a spec object', () => {
-  const person = new HelixSpec({
+  const Person = new HelixSpec({
     id: faker.random.number()
   })
-  const fixture = person.generate()
+  const fixture = Person.generate()
 
   expect(fixture.id).toBeTruthy()
 })
@@ -70,6 +70,15 @@ test('Can generate multiple specs', () => {
   expect(fixture[0].id).not.toBe(fixture[1].id)
 })
 
+test('Creates an empty array if we call generate(0)', () => {
+  const Person = new HelixSpec({
+    id: faker.random.number()
+  })
+
+  const fixture = Person.generate(0)
+  expect(fixture).toEqual([])
+})
+
 test('Can generate nested un-generated spec', () => {
   const PersonSpec = new HelixSpec({
     id: faker.random.number(),