refactor: remove isAbsolute and replace with path.isAbsolute (#405)

path.isAbsolute added in node v0.11.2

lib/reporter.js

@@ -20,14 +20,6 @@ var globalCoverageMap = require('./coverage-map')
 var reports = require('./report-creator')
 const hasOwnProperty = Object.prototype.hasOwnProperty
 
-function isAbsolute (file) {
-  if (path.isAbsolute) {
-    return path.isAbsolute(file)
-  }
-
-  return path.resolve(file) === path.normalize(file)
-}
-
 // TODO(vojta): inject only what required (config.basePath, config.coverageReporter)
 var CoverageReporter = function (rootConfig, helper, logger, emitter) {
   var log = logger.create('coverage')
@@ -58,7 +50,7 @@ var CoverageReporter = function (rootConfig, helper, logger, emitter) {
 
   function normalize (key) {
     // Exclude keys will always be relative, but covObj keys can be absolute or relative
-    var excludeKey = isAbsolute(key) ? path.relative(basePath, key) : key
+    var excludeKey = path.isAbsolute(key) ? path.relative(basePath, key) : key
     // Also normalize for files that start with `./`, etc.
     excludeKey = path.normalize(excludeKey)