Support noRefs dump option

src/dumper.ts

@@ -117,6 +117,8 @@ function State(options: DumpOptions) {
   this.schema      = options['schema'] || DEFAULT_FULL_SCHEMA;
   this.indent      = Math.max(1, (options['indent'] || 2));
   this.lineWidth   = options.lineWidth !== void 0 ? options.lineWidth : 80;
+  this.noRefs      = options['noRefs'] || false;
+
   this.skipInvalid = options['skipInvalid'] || false;
   this.flowLevel   = (common.isNothing(options['flowLevel']) ? -1 : options['flowLevel']);
   this.styleMap    = compileStyleMap(this.schema, options['styles'] || null);
@@ -842,14 +844,16 @@ export interface DumpOptions {
   schema?: SchemaDefinition;
   /** set max line width. (default: 80) */
   lineWidth?: number;
+  /** if `true`, don't convert duplicate objects into references (default: false) */
+  noRefs?: boolean;
 }
 
 export function dump(input, options?: DumpOptions) {
   options = options || {};
 
   var state = new State(options);
 
-  getDuplicateReferences(input, state);
+  if (!options.noRefs) getDuplicateReferences(input, state);
 
   if (writeNode(state, 0, input, true, true)) {
     return state.dump + '\n';

test/dumper.test.ts

@@ -27,4 +27,25 @@ Neque porro quisquam est, qui dolorem ipsum quia dolor sit amet, consectetur, ad
 `);
     });
   });
+
+  suite('noRefs dump option', () => {
+    test('should not use anchors for same objects by default', () => {
+      const obj = { foo: 'bar' };
+
+      expect(safeDump({ a: obj, b: obj })).to.equal(`a: &ref_0
+  foo: bar
+b: *ref_0
+`)
+    });
+
+    test('should not use anchors for same objects if truthy', () => {
+      const obj = { foo: 'bar' };
+
+      expect(safeDump({ a: obj, b: obj }, { noRefs: true })).to.equal(`a:
+  foo: bar
+b:
+  foo: bar
+`)
+    });
+  });
 });