Option to skip space-only patches

emmetio · Nov 14, 2021 · e324bf2 · e324bf2
1 parent 0151531
commit e324bf2
Show file tree

Hide file tree

Showing 3 changed files with 49 additions and 0 deletions.
diff --git a/src/diff.ts b/src/diff.ts
@@ -276,6 +276,10 @@ function getDiff(from: ParsedModel, to: ParsedModel, options: Options): Diff[] {
         ];
     }
 
+    if (options.skipSpace) {
+        diffs = skipSpace(diffs);
+    }
+
     if (options.wordPatches) {
         diffs = wordBounds(diffs);
     }
@@ -326,3 +330,36 @@ function getChangeThreshold(diffs: Diff[]): number {
 
     return changed / unchanged;
 }
+
+function skipSpace(diffs: Diff[]): Diff[] {
+    const result: Diff[] = [];
+    let prev: Diff;
+
+    diffs.forEach(chunk => {
+        let canJoin = false;
+        if (chunk[0] === DIFF_EQUAL) {
+            // If previous chunk is also a text (whitespace), join it with previous
+            canJoin = true;
+        } else if (isSpace(chunk[1])) {
+            if (chunk[0] === DIFF_DELETE) {
+                // Skip deleted space chunk
+                return;
+            }
+
+            chunk[0] = DIFF_EQUAL;
+            canJoin = true;
+        }
+
+        if (canJoin && prev && prev[0] === DIFF_EQUAL) {
+            prev[1] += chunk[1];
+        } else {
+            result.push(prev = chunk);
+        }
+    });
+
+    return result;
+}
+
+function isSpace(text: string): boolean {
+    return /^\s+$/.test(text);
+}
diff --git a/src/options.ts b/src/options.ts
@@ -53,6 +53,9 @@ export interface Options extends ScannerOptions {
     /** Normalize whitespace when extracting content from XML */
     normalizeSpace?: boolean;
 
+    /** Skip space-only diff chunks */
+    skipSpace?: boolean;
+
     /** Reduce ”noise” by removing meaningless whitespace patches */
     compact: boolean;
 

diff --git a/test/diff.ts b/test/diff.ts
@@ -288,6 +288,15 @@ describe('Diff documents', () => {
         equal(diff('<p>foo1 baz</p>', '<p>bar1 baz</p>', { replaceThreshold: 0.4 }), '<p><del>foo1 baz</del><ins>bar1 baz</ins></p>');
     });
 
+    it('skip space patches', () => {
+        const opt = { skipSpace: true };
+        equal(diff('<p>foo bar</p>', '<p>foobar</p>'), '<p>foo<del> </del>bar</p>');
+        equal(diff('<p>foo bar</p>', '<p>foobar</p>', opt), '<p>foobar</p>');
+
+        equal(diff('<p>foobar</p>', '<p>foo bar</p>'), '<p>foo<ins> </ins>bar</p>');
+        equal(diff('<p>foobar</p>', '<p>foo bar</p>', opt), '<p>foo bar</p>');
+    });
+
     it.skip('debug', () => {
         equal(
             diff(