fix: JSON encode URL

solves issue on Windows with backslash path separator

lib/puppeteer-to-istanbul.js

@@ -47,7 +47,7 @@ class PuppeteerToIstanbul {
       const data = jsonPart[url]
       const isLastIteration = index === (keys.length - 1)
 
-      fs.writeSync(fd, `"${url}": ${JSON.stringify(data)}${(isLastIteration ? '' : ',')}`)
+      fs.writeSync(fd, `${JSON.stringify(url)}: ${JSON.stringify(data)}${(isLastIteration ? '' : ',')}`)
     })
     fs.writeSync(fd, '}')
     fs.closeSync(fd)

test/output-files.js

@@ -20,6 +20,7 @@ describe('output-files', () => {
     // Since block-else-not-covered was generated by the above line, this
     // should make a new file with -1 appended to the name
     var newPath = outputFiles.rewritePath('./sample_js/block-else-not-covered-1.js')
+    if (newPath.includes('\\')) newPath = newPath.replace(/\\/g, '/')
     newPath.should.include(storagePath + '/sample_js/block-else-not-covered-1.js')
   })
 
@@ -70,7 +71,7 @@ describe('output-files', () => {
 
   it('appropriately handles modules required via http/https', () => {
     const fixture = require('./fixtures/http-es6-modules.json')
-    const coverageInfo = OutputFiles(fixture).getTransformedCoverage()
+    const coverageInfo = OutputFiles(fixture).getTransformedCoverage().map(info => ({...info, url: info.url.replace(/\\/g, '/')}))
 
     coverageInfo[0].url.should.include('js/index.js')
     coverageInfo[1].url.should.include('js/utils/doc_ready.js')