use --name-status

scripts/diff.js

@@ -2,26 +2,20 @@ const chalk = require('chalk');
 const deepDiff = require('deep-diff');
 const {
   getMergeBase,
-  getGitDiffPathList,
   getFileContent,
+  getGitDiffStatuses,
 } = require('./lib/git.js');
 
 // Note: This does not detect renamed files
 /**
- * @param {string} base
- * @param {string} head
- * @param {string} path
+ * @param {string} baseCommit
+ * @param {string} headCommit
+ * @param {string} basePath
  */
-function getBaseAndHeadContents(base, head, path) {
-  let baseContent;
-  let headContent;
-  try {
-    baseContent = JSON.parse(getFileContent(base, path));
-  } catch {}
-  try {
-    headContent = JSON.parse(getFileContent(head, path));
-  } catch {}
-  return { base: baseContent, head: headContent };
+function getBaseAndHeadContents(baseCommit, basePath, headCommit, headPath) {
+  const base = JSON.parse(getFileContent(baseCommit, basePath));
+  const head = JSON.parse(getFileContent(headCommit, headPath));
+  return { base, head };
 }
 
 /**
@@ -87,19 +81,26 @@ function mergeAsMap(items) {
  * @param {string} base
  * @param {string} head
  */
-function getDiffs(base, head) {
+function getDiffs(base, head = '') {
   const namedDescriptions = [];
-  for (const path of getGitDiffPathList(base, head)) {
-    if (!path.endsWith('.json') || !path.includes('/')) {
+  for (const status of getGitDiffStatuses(base, head)) {
+    if (!status.headPath.endsWith('.json') || !status.headPath.includes('/')) {
       continue;
     }
-    const contents = getBaseAndHeadContents(base, head, path);
-    if (!contents.base || !contents.head) {
+
+    // Note that A means Added for git while it means Array for deep-diff
+    if (status.value === 'A' || status.value === 'D') {
       namedDescriptions.push({
-        name: path.replace(/\//g, '.').slice(0, -5), // trim file extension
-        description: contents.base ? 'Entirely removed' : 'Newly added',
+        name: status.basePath.replace(/\//g, '.').slice(0, -5), // trim file extension
+        description: status.value === 'A' ? 'Newly added' : 'Entirely removed',
       });
     } else {
+      const contents = getBaseAndHeadContents(
+        base,
+        status.basePath,
+        head,
+        status.headPath,
+      );
       namedDescriptions.push(
         ...deepDiff.diff(contents.base, contents.head).map(describeDiffItem),
       );
@@ -109,7 +110,7 @@ function getDiffs(base, head) {
 }
 
 if (require.main === module) {
-  let [base = 'origin/HEAD', head = '*'] = process.argv.slice(2);
+  let [base = 'origin/HEAD', head] = process.argv.slice(2);
   for (const [key, values] of getDiffs(getMergeBase(base, head), head)) {
     console.log(chalk`{bold ${key}}:`);
     for (const value of values) {

scripts/lib/git.js

@@ -4,7 +4,7 @@ const child_process = require('child_process');
  * @param {string} x
  * @param {string} y
  */
-function getMergeBase(x, y) {
+function getMergeBase(x, y = "HEAD") {
   return child_process
     .execSync(`git merge-base ${x} ${y}`, { encoding: 'utf-8' })
     .trim();
@@ -14,12 +14,21 @@ function getMergeBase(x, y) {
  * @param {string} base
  * @param {string} head
  */
-function getGitDiffPathList(base, head) {
+function getGitDiffStatuses(base, head) {
+  function parseFields(fields) {
+    return {
+      value: fields[0],
+      headPath: fields[2] || fields[1],
+      basePath: fields[1]
+    };
+  }
+
   return child_process
-    .execSync(`git diff --name-only ${base} ${head}`, { encoding: 'utf-8' })
+    .execSync(`git diff --name-status ${base} ${head}`, { encoding: 'utf-8' })
     .trim()
     .split('\n')
-    .map(path => path.trim()); // because the line ending could be \r\n
+    .map(line => line.split("\t"))
+    .map(parseFields);
 }
 
 /**
@@ -37,6 +46,6 @@ function getFileContent(commit, path) {
 
 module.exports = {
   getMergeBase,
-  getGitDiffPathList,
+  getGitDiffStatuses,
   getFileContent,
 };