make sure delete alter the data array and also provides deleteAll() method

Author: lhr0909

src/decorator/predicate.ts

@@ -118,4 +118,9 @@ export interface IPredicate<T, U = void> {
    * Remove a list of nodes.
    */
   delete(nodes: T[]): IPredicate<T, U>;
+
+  /**
+   * Removes all nodes from the predicate.
+   */
+  deleteAll(): IPredicate<T, U>;
 }

src/transaction/mutation-builder.ts

@@ -95,7 +95,11 @@ export class MutationBuilder {
 
   public getDeleteNQuadsString(): string {
     const quads = this.getDeleteNQuads();
-    return new Writer({ format: 'N-Quads' }).quadsToString(quads);
+    const quadsString = new Writer({ format: 'N-Quads' }).quadsToString(quads);
+
+    const lines = quadsString.split('\n');
+
+    return Array.from(new Set(lines)).join('\n');
   }
 
   public getDeleteNQuads(): Quad[] {

src/transaction/transaction.ts

@@ -76,9 +76,9 @@ export class Transaction<T extends Object, V> implements ITransaction<T> {
     return new MutationBuilder(this.diff, this.tempIDS).getSetNQuadsString();
   }
 
-  public delete(node: T): void;
-  public delete(nodes: T[]): void;
-  public delete(nodeOrNodes: T | T[]) {
+  public delete(node: T): ITransaction<T>;
+  public delete(nodes: T[]): ITransaction<T>;
+  public delete(nodeOrNodes: T | T[]): ITransaction<T> {
     if (!Array.isArray(nodeOrNodes)) {
       nodeOrNodes = [nodeOrNodes];
     }

tests/delete.spec.ts

@@ -45,10 +45,24 @@ describe('Delete handling', function() {
     transaction.delete(kamil);
     transaction.tree[0].friends.delete(jane);
 
+    // XXX: here kamil is not deleted in the friends predicate
+    expect(transaction.tree[0].friends.get().length).toBe(1);
+
+    expect(transaction.getDeleteNQuadsString()).toEqual(
+      `<0x3> * * .
+<0x2> * * .
+<0x1> <Person.friends> <0x2> .
+`
+    );
+
+    transaction.tree[0].friends.deleteAll();
+    expect(transaction.tree[0].friends.get().length).toBe(0);
+
     expect(transaction.getDeleteNQuadsString()).toEqual(
       `<0x3> * * .
 <0x2> * * .
 <0x1> <Person.friends> <0x2> .
+<0x1> <Person.friends> <0x3> .
 `
     );
   });

tests/perf.spec.ts

@@ -1,5 +1,3 @@
-// @ts-ignore
-import * as util from 'util';
 
 import { IPredicate, Node, Predicate, Property, TransactionBuilder, Uid } from '../src';
 
@@ -77,15 +75,14 @@ describe('Performance testing', () => {
     console.timeEnd('Second');
   });
 
-  it.only('Fuzz with random data', () => {
+  it('Fuzz with random data', () => {
     interface IStation {
       uid: string;
       name: string;
       connects: IStation[];
     }
 
     @Node()
-    // @ts-ignore
     class Station {
       @Uid()
       uid: string;