@@ -60,6 +60,16 @@ describe('@ngtools/json-schema', () => {
       proto.a[1] = 'INVALID';
       expect(proto.a).toEqual(['v2', null, null, 'v3']);
     });
+
+    it('supports default values', () => {
+      const proto: any = Object.create(null);
+      const schema = new RootSchemaTreeNode(proto, {
+        value: valueJson,
+        schema: schemaJson
+      });
+
+      expect(schema.children['b'].get()).toEqual('default');
+    });
   });
 
 });
@@ -97,7 +97,7 @@ export abstract class SchemaTreeNode<T> implements SchemaNode {
   get itemPrototype(): SchemaTreeNode<any> | null { return null; }
 
   abstract get(): T;
-  set(v: T, force = false) {
+  set(v: T, init = false, force = false) {
     if (!this.readOnly) {
       throw new MissingImplementationError();
     }
@@ -220,10 +220,10 @@ export class OneOfSchemaTreeNode extends NonLeafSchemaTreeNode<any> {
     }
 
     this._currentTypeHolder = proto;
-    this._currentTypeHolder.set(v, true);
+    this._currentTypeHolder.set(v, false, true);
   }
 
-  set(v: any, force = false) {
+  set(v: any, init = false, force = false) {
     return this._set(v, false, force);
   }
 
@@ -338,7 +338,6 @@ export class ArraySchemaTreeNode extends NonLeafSchemaTreeNode<Array<any>> {
     const schema = this._schema;
     const forward = this._forward;
 
-    this._defined = !!value;
     this._value = Object.create(null);
     this._dirty = this._dirty || !init;
 
@@ -361,8 +360,8 @@ export class ArraySchemaTreeNode extends NonLeafSchemaTreeNode<Array<any>> {
     }
   }
 
-  set(v: any, force = false) {
-    return this._set(v, false, force);
+  set(v: any, init = false, force = false) {
+    return this._set(v, init, force);
   }
 
   isCompatible(v: any) { return Array.isArray(v); }
@@ -395,7 +394,7 @@ export class RootSchemaTreeNode extends ObjectSchemaTreeNode {
 
 /** A leaf in the schema tree. Must contain a single primitive value. */
 export abstract class LeafSchemaTreeNode<T> extends SchemaTreeNode<T> {
-  private _default: T;
+  protected _default: T;
 
   constructor(metaData: TreeNodeConstructorArgument<T>) {
     super(metaData);
@@ -410,13 +409,13 @@ export abstract class LeafSchemaTreeNode<T> extends SchemaTreeNode<T> {
       return this._forward.get();
     }
     if (!this.defined) {
-      return this._default !== undefined ? this._default : undefined;
+      return 'default' in this._schema ? this._default : undefined;
     }
     return this._value === undefined
       ? undefined
       : (this._value === null ? null : this.convert(this._value));
   }
-  set(v: T, force = false) {
+  set(v: T, init = false, force = false) {
     if (this.readOnly && !force) {
       throw new SettingReadOnlyPropertyError();
     }
@@ -428,7 +427,7 @@ export abstract class LeafSchemaTreeNode<T> extends SchemaTreeNode<T> {
       }
     }
 
-    this.dirty = true;
+    this.dirty = !init;
     this._value = convertedValue;
   }
 
@@ -438,7 +437,10 @@ export abstract class LeafSchemaTreeNode<T> extends SchemaTreeNode<T> {
   }
 
   get defaultValue(): T {
-    return 'default' in this._schema ? this._default : null;
+    return this.hasDefault ? this._default : null;
+  }
+  get hasDefault() {
+    return 'default' in this._schema;
   }
 
   abstract convert(v: any): T;
@@ -462,20 +464,20 @@ class StringSchemaTreeNode extends LeafSchemaTreeNode<string> {
 
 
 class EnumSchemaTreeNode extends StringSchemaTreeNode {
-  private _enumValues: string[];
-
   constructor(metaData: TreeNodeConstructorArgument<string>) {
     super(metaData);
 
     if (!Array.isArray(metaData.schema['enum'])) {
       throw new InvalidSchema();
     }
-    this._enumValues = [].concat(metaData.schema['enum']);
-    this.set(metaData.value, true);
+    if (this.hasDefault && !this._isInEnum(this._default)) {
+      throw new InvalidSchema();
+    }
+    this.set(metaData.value, true, true);
   }
 
   protected _isInEnum(value: string) {
-    return this._enumValues.some(v => v === value);
+    return this._schema['enum'].some((v: string) => v === value);
   }
 
   isCompatible(v: any) {
 
@@ -8,6 +8,10 @@
       "items": {
         "enum": [ "v1", "v2", "v3" ]
       }
+    },
+    "b": {
+      "enum": [ "default", "v1", "v2" ],
+      "default": "default"
     }
   }
 }
@@ -1,8 +1,8 @@
 {
   "a": [
-    null,
+    "v2",
     "v1",
-    null,
+    "v2",
     "v3"
   ]
 }
Original file line number	Diff line number	Diff line change
`@@ -97,7 +97,7 @@ export abstract class SchemaTreeNode<T> implements SchemaNode {`
`97`	`97`	`get itemPrototype(): SchemaTreeNode<any> \| null { return null; }`
`98`	`98`
`99`	`99`	`abstract get(): T;`
`100`		`- set(v: T, force = false) {`
	`100`	`+ set(v: T, init = false, force = false) {`
`101`	`101`	`if (!this.readOnly) {`
`102`	`102`	`throw new MissingImplementationError();`
`103`	`103`	`}`
`@@ -220,10 +220,10 @@ export class OneOfSchemaTreeNode extends NonLeafSchemaTreeNode<any> {`
`220`	`220`	`}`
`221`	`221`
`222`	`222`	`this._currentTypeHolder = proto;`
`223`		`- this._currentTypeHolder.set(v, true);`
	`223`	`+ this._currentTypeHolder.set(v, false, true);`
`224`	`224`	`}`
`225`	`225`
`226`		`- set(v: any, force = false) {`
	`226`	`+ set(v: any, init = false, force = false) {`
`227`	`227`	`return this._set(v, false, force);`
`228`	`228`	`}`
`229`	`229`
`@@ -338,7 +338,6 @@ export class ArraySchemaTreeNode extends NonLeafSchemaTreeNode<Array<any>> {`
`338`	`338`	`const schema = this._schema;`
`339`	`339`	`const forward = this._forward;`
`340`	`340`
`341`		`- this._defined = !!value;`
`342`	`341`	`this._value = Object.create(null);`
`343`	`342`	`this._dirty = this._dirty \|\| !init;`
`344`	`343`
`@@ -361,8 +360,8 @@ export class ArraySchemaTreeNode extends NonLeafSchemaTreeNode<Array<any>> {`
`361`	`360`	`}`
`362`	`361`	`}`
`363`	`362`
`364`		`- set(v: any, force = false) {`
`365`		`- return this._set(v, false, force);`
	`363`	`+ set(v: any, init = false, force = false) {`
	`364`	`+ return this._set(v, init, force);`
`366`	`365`	`}`
`367`	`366`
`368`	`367`	`isCompatible(v: any) { return Array.isArray(v); }`
`@@ -395,7 +394,7 @@ export class RootSchemaTreeNode extends ObjectSchemaTreeNode {`
`395`	`394`
`396`	`395`	`/** A leaf in the schema tree. Must contain a single primitive value. */`
`397`	`396`	`export abstract class LeafSchemaTreeNode<T> extends SchemaTreeNode<T> {`
`398`		`- private _default: T;`
	`397`	`+ protected _default: T;`
`399`	`398`
`400`	`399`	`constructor(metaData: TreeNodeConstructorArgument<T>) {`
`401`	`400`	`super(metaData);`
`@@ -410,13 +409,13 @@ export abstract class LeafSchemaTreeNode<T> extends SchemaTreeNode<T> {`
`410`	`409`	`return this._forward.get();`
`411`	`410`	`}`
`412`	`411`	`if (!this.defined) {`
`413`		`- return this._default !== undefined ? this._default : undefined;`
	`412`	`+ return 'default' in this._schema ? this._default : undefined;`
`414`	`413`	`}`
`415`	`414`	`return this._value === undefined`
`416`	`415`	`? undefined`
`417`	`416`	`: (this._value === null ? null : this.convert(this._value));`
`418`	`417`	`}`
`419`		`- set(v: T, force = false) {`
	`418`	`+ set(v: T, init = false, force = false) {`
`420`	`419`	`if (this.readOnly && !force) {`
`421`	`420`	`throw new SettingReadOnlyPropertyError();`
`422`	`421`	`}`
`@@ -428,7 +427,7 @@ export abstract class LeafSchemaTreeNode<T> extends SchemaTreeNode<T> {`
`428`	`427`	`}`
`429`	`428`	`}`
`430`	`429`
`431`		`- this.dirty = true;`
	`430`	`+ this.dirty = !init;`
`432`	`431`	`this._value = convertedValue;`
`433`	`432`	`}`
`434`	`433`
`@@ -438,7 +437,10 @@ export abstract class LeafSchemaTreeNode<T> extends SchemaTreeNode<T> {`
`438`	`437`	`}`
`439`	`438`
`440`	`439`	`get defaultValue(): T {`
`441`		`- return 'default' in this._schema ? this._default : null;`
	`440`	`+ return this.hasDefault ? this._default : null;`
	`441`	`+ }`
	`442`	`+ get hasDefault() {`
	`443`	`+ return 'default' in this._schema;`
`442`	`444`	`}`
`443`	`445`
`444`	`446`	`abstract convert(v: any): T;`
`@@ -462,20 +464,20 @@ class StringSchemaTreeNode extends LeafSchemaTreeNode<string> {`
`462`	`464`
`463`	`465`
`464`	`466`	`class EnumSchemaTreeNode extends StringSchemaTreeNode {`
`465`		`- private _enumValues: string[];`
`466`		`-`
`467`	`467`	`constructor(metaData: TreeNodeConstructorArgument<string>) {`
`468`	`468`	`super(metaData);`
`469`	`469`
`470`	`470`	`if (!Array.isArray(metaData.schema['enum'])) {`
`471`	`471`	`throw new InvalidSchema();`
`472`	`472`	`}`
`473`		`- this._enumValues = [].concat(metaData.schema['enum']);`
`474`		`- this.set(metaData.value, true);`
	`473`	`+ if (this.hasDefault && !this._isInEnum(this._default)) {`
	`474`	`+ throw new InvalidSchema();`
	`475`	`+ }`
	`476`	`+ this.set(metaData.value, true, true);`
`475`	`477`	`}`
`476`	`478`
`477`	`479`	`protected _isInEnum(value: string) {`
`478`		`- return this._enumValues.some(v => v === value);`
	`480`	`+ return this._schema['enum'].some((v: string) => v === value);`
`479`	`481`	`}`
`480`	`482`
`481`	`483`	`isCompatible(v: any) {`
Original file line number	Diff line number	Diff line change
`@@ -8,6 +8,10 @@`
`8`	`8`	`"items": {`
`9`	`9`	`"enum": [ "v1", "v2", "v3" ]`
`10`	`10`	`}`
	`11`	`+ },`
	`12`	`+ "b": {`
	`13`	`+ "enum": [ "default", "v1", "v2" ],`
	`14`	`+ "default": "default"`
`11`	`15`	`}`
`12`	`16`	`}`
`13`	`17`	`}`
Original file line number	Diff line number	Diff line change
`@@ -1,8 +1,8 @@`
`1`	`1`	`{`
`2`	`2`	`"a": [`
`3`		`- null,`
	`3`	`+ "v2",`
`4`	`4`	`"v1",`
`5`		`- null,`
	`5`	`+ "v2",`
`6`	`6`	`"v3"`
`7`	`7`	`]`
`8`	`8`	`}`