test(packaging): added test for source map correctness

tools/source-map-test/parseMap.js

@@ -0,0 +1,57 @@
+#!/usr/bin/env node
+
+const vlq = require('vlq');
+const fs = require('fs');
+const path = require('path');
+
+module.exports =
+    function getMappings(bundlePath) {
+  const sourceMap = JSON.parse(getFile(`${bundlePath}.map`));
+  const sourcesContent = sourceMap.sourcesContent.map(file => file.split('\n'));
+  const bundleLines = getFile(bundlePath).split('\n');
+
+  let sourceLines = sourcesContent[0];
+  let sourceFileIndex = 0;
+  let sourceLineIndex = 0;
+  let sourceColIndex = 0;
+
+  return decodeLines(sourceMap).reduce((matchData, mapLine, genLineIndex) => {
+    mapLine.forEach((segment, index) => {
+      if (segment.length) {
+        const [genColDiff, sourceFileDiff, sourceLineDiff, sourceColDiff] = segment;
+
+        // if source file changes, grab new file from sourcesContent
+        if (sourceFileDiff !== 0) {
+          sourceFileIndex += sourceFileDiff;
+          sourceLines = sourcesContent[sourceFileIndex];
+        }
+
+        const genText = bundleLines[genLineIndex].trim();
+        const sourceText = sourceLines[sourceLineIndex + sourceLineDiff].trim();
+
+        // only record mappings that are long enough to be meaningful
+        if (index === 0 && genText.length > 15 && sourceText.length > 15) {
+          matchData.push({
+            genLineIndex,
+            sourceLineIndex,
+            sourceFile: sourceMap.sources[sourceFileIndex], genText, sourceText
+          });
+        }
+
+        sourceLineIndex += sourceLineDiff;
+        sourceColIndex += sourceColDiff;
+      }
+    });
+
+    return matchData;
+  }, []);
+}
+
+function getFile(filePath) {
+  return fs.readFileSync(path.resolve(process.cwd(), filePath), 'UTF-8');
+}
+
+function decodeLines(sourceMap) {
+  return sourceMap.mappings.split(';').map(
+      line => { return line.split(',').map(seg => vlq.decode(seg)); });
+}