Add support for dynamic labels in set and remove

.changeset/hip-kings-behave.md

@@ -0,0 +1,15 @@
+---
+"@neo4j/cypher-builder": minor
+---
+
+Add support for dynamic labels by passing an expression to `node.label`:
+
+```javascript
+new Cypher.Match(new Cypher.Pattern(movie)).set(movie.label(Cypher.labels(anotherNode)));
+```
+
+```cypher
+MATCH (this0)
+SET
+    this0:$(labels(this1))
+```

src/clauses/sub-clauses/Remove.test.ts

@@ -45,6 +45,19 @@ REMOVE this0:NewLabel"
         expect(queryResult.cypher).toMatchInlineSnapshot(`
 "MATCH (this0)-[]->(this1)
 REMOVE this0:NewLabel, this1:\`Another Label\`"
+`);
+
+        expect(queryResult.params).toMatchInlineSnapshot(`{}`);
+    });
+
+    test("Remove dynamic labels", () => {
+        const movie = new Cypher.Node();
+        const clause = new Cypher.Match(new Cypher.Pattern(movie)).remove(movie.label(Cypher.labels(movie)));
+
+        const queryResult = clause.build();
+        expect(queryResult.cypher).toMatchInlineSnapshot(`
+"MATCH (this0)
+REMOVE this0:$(labels(this0))"
 `);
 
         expect(queryResult.params).toMatchInlineSnapshot(`{}`);

src/clauses/sub-clauses/Set.test.ts

@@ -70,4 +70,18 @@ SET
 
         expect(queryResult.params).toMatchInlineSnapshot(`{}`);
     });
+
+    test("Set dynamic labels", () => {
+        const movie = new Cypher.Node();
+        const clause = new Cypher.Match(new Cypher.Pattern(movie)).set(movie.label(Cypher.labels(movie)));
+
+        const queryResult = clause.build();
+        expect(queryResult.cypher).toMatchInlineSnapshot(`
+"MATCH (this0)
+SET
+    this0:$(labels(this0))"
+`);
+
+        expect(queryResult.params).toMatchInlineSnapshot(`{}`);
+    });
 });

src/references/Label.ts

@@ -17,6 +17,7 @@
  * limitations under the License.
  */
 
+import type { Expr } from "..";
 import { CypherASTNode } from "../CypherASTNode";
 import type { CypherEnvironment } from "../Environment";
 import type { NodeRef } from "../references/NodeRef";
@@ -28,7 +29,7 @@ import { escapeLabel } from "../utils/escape";
  * @example `:Movie`
  */
 export class Label extends CypherASTNode {
-    private readonly node: NodeRef;
+    protected readonly node: NodeRef;
     private readonly label: string;
 
     /**
@@ -51,3 +52,23 @@ export class Label extends CypherASTNode {
         return addLabelToken(env.config.labelOperator, escapeLabel(this.label));
     }
 }
+
+export class DynamicLabel extends Label {
+    private readonly expr: Expr;
+
+    /**
+     * @hidden
+     */
+    constructor(node: NodeRef, expr: Expr) {
+        super(node, "");
+        this.expr = expr;
+    }
+
+    /** @internal */
+    public getCypher(env: CypherEnvironment): string {
+        const nodeId = this.node.getCypher(env);
+        const exprStr = `$(${this.expr.getCypher(env)})`;
+        const labelStr = addLabelToken(env.config.labelOperator, exprStr);
+        return `${nodeId}${labelStr}`;
+    }
+}

src/references/NodeRef.ts

@@ -17,9 +17,10 @@
  * limitations under the License.
  */
 
+import type { Expr } from "..";
 import { HasLabel } from "../expressions/HasLabel";
 import type { LabelExpr } from "../expressions/labels/label-expressions";
-import { Label } from "./Label";
+import { DynamicLabel, Label } from "./Label";
 import type { NamedReference } from "./Variable";
 import { Variable } from "./Variable";
 
@@ -44,8 +45,12 @@ export class NodeRef extends Variable {
         }
     }
 
-    public label(label: string): Label {
-        return new Label(this, label);
+    public label(label: string | Expr): Label {
+        if (typeof label === "string") {
+            return new Label(this, label);
+        } else {
+            return new DynamicLabel(this, label);
+        }
     }
 }