Merge pull request #115 from codeclimate/abh-wf-skip-minified-eslint

Heuristically filter out minified files

bin/eslint.js

@@ -15,6 +15,7 @@ var glob = require("glob");
 var options = { extensions: [".js"], ignore: true, reset: false, useEslintrc: true };
 var cli; // instantiation delayed until after options are (potentially) modified
 var debug = false;
+var BatchSanitizer = require("../lib/batch_sanitizer");
 var checks = require("../lib/checks");
 var validateConfig = require("../lib/validate_config");
 var computeFingerprint = require("../lib/compute_fingerprint");
@@ -181,17 +182,19 @@ function analyzeFiles() {
   var batchNum = 0
     , batchSize = 10
     , batchFiles
-    , batchReport;
+    , batchReport
+    , sanitizedBatchFiles;
 
   while(analysisFiles.length > 0) {
     batchFiles = analysisFiles.splice(0, batchSize);
+    sanitizedBatchFiles = (new BatchSanitizer(batchFiles)).sanitizedFiles();
 
     if (debug) {
       process.stderr.write("Analyzing: " + batchFiles + "\n");
     }
 
     runWithTiming("analyze-batch-" + batchNum, function() {
-       batchReport = cli.executeOnFiles(batchFiles);
+       batchReport = cli.executeOnFiles(sanitizedBatchFiles);
     });
     runWithTiming("report-batch" + batchNum, function() {
       batchReport.results.forEach(function(result) {

lib/batch_sanitizer.js

@@ -0,0 +1,41 @@
+var fs = require("fs");
+
+var MINIFIED_AVG_LINE_LENGTH_CUTOFF = 100;
+
+function BatchSanitizer(files, stderr) {
+  this.files = files;
+  this.stderr = stderr || process.stderr;
+}
+
+BatchSanitizer.prototype.sanitizedFiles = function() {
+  var sanitizedFiles = [];
+
+  for(var i = 0; i < this.files.length; i++) {
+    if (this.isMinified(this.files[i])) {
+      this.stderr.write("WARN: Skipping " + this.files[i] + ": it appears to be minified\n");
+    } else {
+      sanitizedFiles.push(this.files[i]);
+    }
+  }
+
+  return sanitizedFiles;
+};
+
+BatchSanitizer.prototype.isMinified = function(path) {
+  var buf = fs.readFileSync(path)
+    , newline = "\n".charCodeAt(0)
+    , lineCount = 0
+    , charsSeen = 0;
+
+  for(var i = 0; i < buf.length; i++) {
+    if (buf[i] === newline) {
+      lineCount++;
+    } else {
+      charsSeen++;
+    }
+  }
+
+  return (charsSeen / lineCount) >= MINIFIED_AVG_LINE_LENGTH_CUTOFF;
+};
+
+module.exports = BatchSanitizer;

test/batch_sanitizer_test.js

@@ -0,0 +1,17 @@
+var BatchSanitizer = require("../lib/batch_sanitizer")
+  , expect = require("chai").expect;
+
+describe("BatchSanitizer module", function() {
+  describe(".sanitizedFiles()", function() {
+    it("filters out files that appear minified", function() {
+      var stderr = { contents: "", write: function(str) { this.contents += str; } }
+        , sanitizer = new BatchSanitizer(
+            ["./test/fixtures/minified_batch/minified.js", "./test/fixtures/minified_batch/unminified.js"],
+            stderr
+          );
+
+      expect(sanitizer.sanitizedFiles()).to.eql(["./test/fixtures/minified_batch/unminified.js"]);
+      expect(stderr.contents).to.match(/WARN: Skipping/);
+    });
+  });
+});