feat: new hasChanged method

README.md

@@ -117,6 +117,10 @@ The returned sourcemap has two (non-enumerable) methods attached for convenience
 code += '\n//# sourceMappingURL=' + map.toUrl();
 ```
 
+### s.hasChanged()
+
+Indicates if the string has been changed.
+
 ### s.indent( prefix[, options] )
 
 Prefixes each line of the string with `prefix`. If `prefix` is not supplied, the indentation will be guessed from the original content, falling back to a single tab character. Returns `this`.

index.d.ts

@@ -217,6 +217,11 @@ export default class MagicString {
   isEmpty(): boolean;
   length(): number;
 
+  /**
+   * Indicates if the string has been changed.
+   */
+  hasChanged(): boolean;
+
   original: string;
   /**
    * Returns the generated string.

src/MagicString.js

@@ -713,6 +713,10 @@ export default class MagicString {
 		return this;
 	}
 
+	hasChanged() {
+		return this.original !== this.toString();
+	}
+
 	replace(searchValue, replacement) {
 		function getReplacement(match) {
 			if (typeof replacement === 'string') {

test/MagicString.js

@@ -1278,6 +1278,26 @@ describe('MagicString', () => {
 		});
 	});
 
+	describe('hasChanged', () => {
+		it('should works', () => {
+			const s = new MagicString(' abcde   fghijkl ');
+
+			assert.ok(!s.hasChanged());
+
+			assert.ok(s.clone().prepend('  ').hasChanged());
+			assert.ok(s.clone().overwrite(1, 2, 'b').hasChanged());
+			assert.ok(s.clone().remove(1, 6).hasChanged());
+
+			s.trim();
+
+			assert.ok(s.hasChanged());
+
+			const clone = s.clone();
+
+			assert.ok(clone.hasChanged());
+		});
+	});
+
 	describe('replace', () => {
 		it('works with string replace', () => {
 			const code = '1 2 1 2';