feat(core): support groupBy directive

.gitignore

@@ -116,3 +116,4 @@ dist
 .yarn/unplugged
 .yarn/build-state.yml
 .pnp.*
+.idea

packages/core/README.md

@@ -171,6 +171,7 @@ you can also use
 
 Query and Edge directives:
 - **cascade**
+- **groupBy**
 
 Query only directives:
 - **ignoreReflex**

packages/core/src/directive/directive-builder.ts

@@ -3,12 +3,14 @@ import { OpBuilderTypes } from '../operator';
 import { DirectiveArgs, Directive } from './directive';
 import { extractRefs } from '../ref';
 import { RecurseBuilderArgs } from './recurse'
+import { GroupByBuilderArgs } from './group-by'
 
 export interface DirectiveBuilderArgs {
   filter: [OpBuilderTypes];
   cascade: undefined;
   ignoreReflex: undefined;
   recurse: RecurseBuilderArgs;
+  groupBy: GroupByBuilderArgs;
 }
 
 export class DirectiveBuilder<T extends keyof DirectiveBuilderArgs = keyof DirectiveBuilderArgs> {

packages/core/src/directive/directive.ts

@@ -1,12 +1,14 @@
 import { LogicalOperator, Operator } from '../operator';
 import { Param } from '../param';
 import { RecurseArgs } from './recurse';
+import { GroupByArgs } from './group-by';
 
 export interface DirectiveArgs {
   filter: LogicalOperator | Operator;
   cascade: undefined;
   ignoreReflex: undefined;
   recurse: RecurseArgs | undefined;
+  groupBy: GroupByArgs;
 }
 
 export class Directive<T extends keyof DirectiveArgs = any> {
@@ -22,6 +24,7 @@ export class Directive<T extends keyof DirectiveArgs = any> {
   params(): Param[] {
     const argsValues = !this.hasArgs() ? []
     : Array.isArray(this.args) ? this.args
+    : typeof this.args!=='object'? [this.args]
     : Object.entries(this.args).map(([_, value]) => value);
 
     return argsValues.reduce((r, arg) => {
@@ -36,9 +39,10 @@ export class Directive<T extends keyof DirectiveArgs = any> {
   toString() {
     const argsList = !this.hasArgs() ? []
       : Array.isArray(this.args) ? this.args
+      : typeof this.args!=='object'? [this.args]
       : Object.entries(this.args).map(([key, value]) => `${key}: ${value}`);
 
-    return `@${this.name}${
+    return `@${this.name.toLowerCase()}${
       !argsList.length ? '' : `(${argsList.join(', ')})`
     }`;
   }

packages/core/src/directive/group-by.ts

@@ -0,0 +1,8 @@
+
+import { Param, ParamBuilder } from '../param';
+
+/** @see https://dgraph.io/docs/query-language/groupby/ */
+// predicate
+export type GroupByBuilderArgs = string | ParamBuilder<'string'>
+
+export type GroupByArgs = string | Param<'string'>;

packages/core/src/edge/edge-builder.ts

@@ -17,6 +17,7 @@ import {
   GenericProjection,
 } from './common';
 import { DirectiveBuilder } from '../directive';
+import { GroupByBuilderArgs } from '../directive/group-by';
 import { Ref } from '../ref';
 import { Runnable } from '../types';
 import {
@@ -247,6 +248,11 @@ export class EdgeBuilder extends FieldBuilder {
     return this;
   }
 
+  groupBy(predicate: GroupByBuilderArgs) {
+    this.directives.groupBy = new DirectiveBuilder('groupBy', predicate);
+    return this;
+  }
+
   keyToField(key: string) {
     if (['id', 'uid'].includes(key))
       return 'uid';

packages/core/test/directive.test.ts

@@ -15,7 +15,7 @@ describe('Directive test', () => {
 
   it('`@ignoreReflex` directive', () => {
     expect(query().ignoreReflex().toString())
-      .toMatch(/@ignoreReflex \{/);
+      .toMatch(/@ignorereflex \{/);
   });
 
   it('`@recurse` directive no args', () => {
@@ -51,4 +51,9 @@ describe('Directive test', () => {
     expect(myParams[0].getValue()).toEqual('false');
     expect(myParams[1].getValue()).toEqual('5');
   });
+
+  it('`@groupBy` directive', () => {
+    expect(edge({}).groupBy('predicate').toString())
+        .toMatch(/@groupby\(predicate\) \{/);
+  });
 });