webpack resolver: cache instance(s) of resolve function (#1091)

* cache instance(s) of resolve function
* properly report resolver test coverage
- also dropped webpack resolver support for node 0.10 (lol)

resolvers/node/package.json

@@ -7,7 +7,8 @@
     "index.js"
   ],
   "scripts": {
-    "test": "nyc mocha"
+    "test": "nyc mocha",
+    "coveralls": "nyc report --reporter lcovonly && cd ../.. && coveralls < ./resolvers/node/coverage/lcov.info"
   },
   "repository": {
     "type": "git",
@@ -32,6 +33,7 @@
   },
   "devDependencies": {
     "chai": "^3.5.0",
+    "coveralls": "^3.0.0",
     "mocha": "^3.5.3",
     "nyc": "^10.3.2"
   }

resolvers/webpack/index.js

@@ -1,10 +1,9 @@
 var findRoot = require('find-root')
   , path = require('path')
-  , get = require('lodash.get')
+  , get = require('lodash/get')
+  , isEqual = require('lodash/isEqual')
   , find = require('array-find')
   , interpret = require('interpret')
-  // not available on 0.10.x
-  , isAbsolute = path.isAbsolute || require('is-absolute')
   , fs = require('fs')
   , coreLibs = require('node-libs-browser')
   , resolve = require('resolve')
@@ -56,7 +55,7 @@ exports.resolve = function (source, file, settings) {
   if (!configPath || typeof configPath === 'string') {
 
       // see if we've got an absolute path
-      if (!configPath || !isAbsolute(configPath)) {
+      if (!configPath || !path.isAbsolute(configPath)) {
         // if not, find ancestral package.json and use its directory as base for the path
         packageDir = findRoot(path.resolve(file))
         if (!packageDir) throw new Error('package not found above ' + file)
@@ -105,7 +104,8 @@ exports.resolve = function (source, file, settings) {
   }
 
   // otherwise, resolve "normally"
-  var resolveSync = createResolveSync(configPath, webpackConfig)
+  var resolveSync = getResolveSync(configPath, webpackConfig)
+
   try {
     return { found: true, path: resolveSync(path.dirname(file), source) }
   } catch (err) {
@@ -114,6 +114,24 @@ exports.resolve = function (source, file, settings) {
   }
 }
 
+var MAX_CACHE = 10
+var _cache = []
+function getResolveSync(configPath, webpackConfig) {
+  var cacheKey = { configPath: configPath, webpackConfig: webpackConfig }
+  var cached = find(_cache, function (entry) { return isEqual(entry.key, cacheKey) })
+  if (!cached) {
+    cached = {
+      key: cacheKey,
+      value: createResolveSync(configPath, webpackConfig)
+    }
+    // put in front and pop last item
+    if (_cache.unshift(cached) > MAX_CACHE) {
+      _cache.pop()
+    }
+  }
+  return cached.value
+}
+
 function createResolveSync(configPath, webpackConfig) {
   var webpackRequire
     , basedir = null
@@ -316,7 +334,7 @@ function findConfigPath(configPath, packageDir) {
     })
 
     // see if we've got an absolute path
-    if (!isAbsolute(configPath)) {
+    if (!path.isAbsolute(configPath)) {
       configPath = path.join(packageDir, configPath)
     }
   } else {

resolvers/webpack/package.json

@@ -5,7 +5,8 @@
   "main": "index.js",
   "scripts": {
     "test": "nyc mocha -t 5s",
-    "report": "nyc report --reporter=html"
+    "report": "nyc report --reporter=html",
+    "coveralls": "nyc report --reporter lcovonly && cd ../.. && coveralls < ./resolvers/webpack/coverage/lcov.info"
   },
   "files": [
     "index.js",
@@ -35,8 +36,7 @@
     "find-root": "^1.1.0",
     "has": "^1.0.1",
     "interpret": "^1.0.0",
-    "is-absolute": "^0.2.3",
-    "lodash.get": "^4.4.2",
+    "lodash": "^4.17.4",
     "node-libs-browser": "^1.0.0 || ^2.0.0",
     "resolve": "^1.4.0",
     "semver": "^5.3.0"
@@ -50,6 +50,7 @@
     "babel-preset-es2015-argon": "^0.1.0",
     "babel-register": "^6.26.0",
     "chai": "^3.4.1",
+    "coveralls": "^3.0.0",
     "mocha": "^2.3.3",
     "nyc": "^7.0.0"
   }