feat: add page

Author: devdigital

src/browser/adapters/puppeteer.js

@@ -5,6 +5,7 @@ const puppeteerAdapter = async delegate => {
   const page = await browser.newPage()
 
   await delegate({
+    context: () => page,
     get: async uri => {
       await page.goto(uri)
       return await page.content()

src/browser/browser.js

@@ -4,6 +4,8 @@ import isFunction from 'inspected/schema/is-function'
 import isRequired from 'inspected/schema/is-required'
 import isObject from 'inspected/schema/is-object'
 
+import pager from './pager'
+
 const createAdapted = adapter => ({
   get: async uri => {
     if (!isRequired(isString)(uri)) {
@@ -12,12 +14,21 @@ const createAdapted = adapter => ({
 
     let content = null
 
-    await adapter(async http => {
-      content = await http.get(uri)
+    await adapter(async adapted => {
+      content = await adapted.get(uri)
     })
 
     return content
   },
+  page: async (uri, delegate) => {
+    if (!isRequired(isString)(uri)) {
+      throw new Error('Uri must be a string.')
+    }
+
+    await adapter(async adapted => {
+      pager(adapted.context(), uri)(delegate)
+    })
+  },
 })
 
 const browser = options => adapter => {
@@ -46,11 +57,12 @@ const browser = options => adapter => {
       throw new Error('Unexpected value, must be a function.')
     }
 
-    await adapter(async http => {
-      await delegate(createAdapted(async process => await process(http)))
+    await adapter(async adapted => {
+      await delegate(createAdapted(async process => await process(adapted)))
     })
   }
 
+  // Provide a subset of functions outside of 'use'
   const funcs = ['get']
 
   funcs.forEach(f => {

src/browser/browser.test.js

@@ -1,5 +1,6 @@
 import browser from './browser'
 import puppeteer from './adapters/puppeteer'
+import { Page } from 'puppeteer/lib/Page'
 
 describe('browser', () => {
   it('should throw when options are not an object', () => {
@@ -38,4 +39,17 @@ describe('browser', () => {
 
     expect(content).toBeTruthy()
   })
+
+  it('should pass configured page function with page context', async () => {
+    const { use } = browser()(puppeteer)
+
+    let result = null
+    await use(async ({ page }) => {
+      await page('http://www.google.com', (context, uri) => {
+        result = { context, uri }
+      })
+    })
+
+    expect(result.context).toBeInstanceOf(Page)
+  })
 })

src/browser/pager.js

@@ -0,0 +1,29 @@
+import isFunction from 'inspected/schema/is-function'
+import isNil from 'inspected/schema/is-nil'
+
+const pager = (context, uri) => async delegate => {
+  if (isNil(delegate)) {
+    throw new Error('delegate must be specified.')
+  }
+
+  if (!isFunction(delegate)) {
+    throw new Error('delegate must be a function.')
+  }
+
+  let currentContext = context
+  let currentUri = uri
+
+  let result = { complete: false }
+  while (result.complete === false) {
+    result = await delegate(currentContext, currentUri)
+
+    if (!result) {
+      break
+    }
+
+    currentContext = result.context
+    currentUri = result.uri
+  }
+}
+
+export default pager

src/browser/pager.test.js

@@ -0,0 +1,32 @@
+import pager from './pager'
+
+describe('pager', () => {
+  it('should throw if delegate is undefined', async () => {
+    await expect(pager()()).rejects.toHaveProperty(
+      'message',
+      'delegate must be specified.'
+    )
+  })
+
+  it('should throw if delegate is null', async () => {
+    await expect(pager()(null)).rejects.toHaveProperty(
+      'message',
+      'delegate must be specified.'
+    )
+  })
+
+  it('should throw if delegate is not a function', async () => {
+    await expect(pager()(false)).rejects.toHaveProperty(
+      'message',
+      'delegate must be a function.'
+    )
+  })
+
+  it('should pass context and uri to delegate', async () => {
+    let result = null
+    await pager({ foo: 'bar' }, 'baz')(
+      async (context, uri) => (result = { context, uri })
+    )
+    expect(result).toEqual({ context: { foo: 'bar' }, uri: 'baz' })
+  })
+})