fix(plugin-example): make the example plugin work with async code

Execute the examples in child processes in order to be able to determine when they truly end.

fix #11

README.md

@@ -105,6 +105,7 @@ mos test --tap | tap-nyan
 - [async-regex-replace](https://github.com/pmarkert/async-regex-replace): regex replacements using asynchronous callback functions
 - [callsites](https://github.com/sindresorhus/callsites): Get callsites from the V8 stack trace API
 - [chalk](https://github.com/chalk/chalk): Terminal string styling done right. Much color.
+- [cross-spawn-async](https://github.com/IndigoUnited/node-cross-spawn-async): Cross platform child_process#spawn
 - [github-url-to-object](https://github.com/zeke/github-url-to-object): Extract user, repo, and other interesting properties from GitHub URLs
 - [glob](https://github.com/isaacs/node-glob): a little globber
 - [meow](https://github.com/sindresorhus/meow): CLI app helper

package.json

@@ -55,6 +55,7 @@
     "async-regex-replace": "1.0.2",
     "callsites": "1.0.0",
     "chalk": "1.1.3",
+    "cross-spawn-async": "2.1.9",
     "github-url-to-object": "2.2.1",
     "glob": "7.0.3",
     "meow": "^3.7.0",

plugins/mos-plugin-example/lib/hook-console-log.js

@@ -0,0 +1,43 @@
+'use strict'
+module.exports = hookConsoleLog
+
+const callsites = require('callsites')
+const removeLastEOL = require('../../remove-last-eol')
+
+const originalLog = console.log
+
+function hookConsoleLog (filePath) {
+  console.log = function () {
+    const site = callsiteForFile(filePath)
+
+    originalLog({
+      message: getRealConsoleOutput.apply(null, arguments),
+      line: site.line,
+    })
+  }
+}
+
+function getRealConsoleOutput () {
+  const originalWrite = process.stdout.write
+
+  let message
+  process.stdout.write = msg => { message = msg }
+
+  originalLog.apply(console, arguments)
+
+  process.stdout.write = originalWrite
+
+  return removeLastEOL(message)
+}
+
+function callsiteForFile (fileName) {
+  const stack = trace()
+  return stack.find(callsite => callsite.file === fileName)
+}
+
+function trace () {
+  return callsites().map(callsite => ({
+    file: callsite.getFileName() || '?',
+    line: callsite.getLineNumber(),
+  }))
+}

plugins/mos-plugin-example/lib/hook-console-log.spec.js

@@ -0,0 +1,2 @@
+'use strict'
+require('./hook-console-log')

plugins/mos-plugin-example/lib/stdout-to-comments.js

@@ -1,72 +1,64 @@
 'use strict'
 module.exports = stdoutToComments
 
-const removeLastEOL = require('../../remove-last-eol')
 const fs = require('fs')
-const callsites = require('callsites')
+const spawn = require('cross-spawn-async')
+const path = require('path')
+const hookPath = path.resolve(__dirname, './hook-console-log')
 
 function stdoutToComments (filePath) {
   return new Promise((resolve, reject) => {
     fs.readFile(filePath, 'utf8', (err, content) => {
       if (err) return reject(err)
 
-      const originalLog = console.log
-      const outputs = []
-
-      console.log = function () {
-        const site = callsiteForFile(filePath)
-
-        outputs.push({
-          message: getRealConsoleOutput.apply(null, arguments),
-          line: site.line,
-        })
-      }
-
-      function getRealConsoleOutput () {
-        const originalWrite = process.stdout.write
-
-        let message
-        process.stdout.write = msg => { message = msg }
-
-        originalLog.apply(console, arguments)
+      const tmpFileName = filePath + Math.random() + '.js'
+      fs.writeFileSync(tmpFileName, addHook({
+        code: content,
+        filePath: tmpFileName,
+      }), 'utf8')
 
-        process.stdout.write = originalWrite
+      const outputs = []
+      let failed = false
 
-        return removeLastEOL(message)
-      }
+      const cp = spawn('node', [tmpFileName])
+      cp.stdout.setEncoding('utf8')
+      cp.stderr.setEncoding('utf8')
+      cp.stdout.on('data', data => {
+        try {
+          eval(`outputs.push(${data})`) // eslint-disable-line no-eval
+        } catch (err) {
+          failed = true
+          reject(err)
+        }
+      })
+      cp.stderr.on('data', data => console.error(data))
+      cp.on('close', code => {
+        fs.unlinkSync(tmpFileName)
 
-      try {
-        require(filePath)
-      } catch (err) {
-        throw err
-      } finally {
-        console.log = originalLog
-      }
+        if (failed) {
+          return
+        }
 
-      resolve(content.split('\n').reduce((contentLines, line, index) => {
-        contentLines.push(line)
+        resolve(content.split('\n').reduce((contentLines, line, index) => {
+          contentLines.push(line)
 
-        const lineNo = index + 1
-        while (outputs.length && outputs[0].line === lineNo) {
-          const matches = (contentLines[contentLines.length - 1] || '').match(/^(\s*)/)
-          const linePadding = matches && matches[0] || ''
-          contentLines.push(linePadding + '//> ' +
-            outputs.shift().message.replace(/\r?\n/g, '\n' + linePadding + '//  '))
-        }
-        return contentLines
-      }, []).join('\n'))
+          const lineNo = index + 1
+          while (outputs.length && outputs[0].line === lineNo) {
+            const matches = (contentLines[contentLines.length - 1] || '').match(/^(\s*)/)
+            const linePadding = matches && matches[0] || ''
+            contentLines.push(linePadding + '//> ' +
+              outputs.shift().message.replace(/\r?\n/g, '\n' + linePadding + '//  '))
+          }
+          return contentLines
+        }, []).join('\n'))
+      })
     })
   })
 }
 
-function callsiteForFile (fileName) {
-  const stack = trace()
-  return stack.find(callsite => callsite.file === fileName)
-}
-
-function trace () {
-  return callsites().map(callsite => ({
-    file: callsite.getFileName() || '?',
-    line: callsite.getLineNumber(),
-  }))
+function addHook (opts) {
+  if (!opts.code.match(/['"]use strict['"]/)) {
+    return `require('${hookPath}')('${opts.filePath}');` + opts.code
+  }
+  return `'use strict';require('${hookPath}')('${opts.filePath}');` + opts.code
 }

plugins/mos-plugin-example/lib/stdout-to-comments.spec.js

@@ -31,6 +31,13 @@ describe('stdoutToComments', () => {
       )
   })
 
+  it('should add the console output to the comments when the code executed asynchronously', () => {
+    return inlineStdoutToComments('setTimeout(() => console.log("Hello world!"), 0)')
+      .then(actual =>
+        expect(actual).to.eq('setTimeout(() => console.log("Hello world!"), 0)\n//> Hello world!')
+      )
+  })
+
   it('should add the multiline console output to the comments', () => {
     return inlineStdoutToComments('console.log("Hello world!\\nHello world!")')
       .then(actual =>