fix(editor): Make inputs dragged to Python Code editor produce working code (#19415)

packages/frontend/editor-ui/src/components/CodeNodeEditor/CodeNodeEditor.vue

@@ -20,6 +20,7 @@ import { useLinter } from './linter';
 import { useSettingsStore } from '@/stores/settings.store';
 import { dropInCodeEditor } from '@/plugins/codemirror/dragAndDrop';
 import type { TargetNodeParameterContext } from '@/Interface';
+import { valueToInsert } from './utils';
 
 export type CodeNodeLanguageOption = CodeNodeEditorLanguage | 'pythonNative';
 
@@ -203,12 +204,11 @@ function onAiLoadEnd() {
 async function onDrop(value: string, event: MouseEvent) {
 	if (!editor.value) return;
 
-	const valueToInsert =
-		props.mode === 'runOnceForAllItems'
-			? value.replace('$json', '$input.first().json').replace(/\$\((.*)\)\.item/, '$($1).first()')
-			: value;
-
-	await dropInCodeEditor(toRaw(editor.value), event, valueToInsert);
+	await dropInCodeEditor(
+		toRaw(editor.value),
+		event,
+		valueToInsert(value, props.language, props.mode),
+	);
 }
 
 defineExpose({

packages/frontend/editor-ui/src/components/CodeNodeEditor/utils.test.ts

@@ -1,5 +1,5 @@
 import * as esprima from 'esprima-next';
-import { walk } from './utils';
+import { valueToInsert, walk } from './utils';
 
 describe('CodeNodeEditor utils', () => {
 	describe('walk', () => {
@@ -41,4 +41,88 @@ const y = f({ a: 'c' })
 			]);
 		});
 	});
+
+	describe('valueToInsert', () => {
+		describe('JavaScript', () => {
+			it('should convert input item correctly, runOnceForAllItems', () => {
+				expect(
+					valueToInsert('{{ $json.foo.bar[0].baz }}', 'javaScript', 'runOnceForAllItems'),
+				).toBe('{{ $input.first().json.foo.bar[0].baz }}');
+			});
+
+			it('should convert input item correctly, runOnceForEachItem', () => {
+				expect(
+					valueToInsert('{{ $json.foo.bar[0].baz }}', 'javaScript', 'runOnceForEachItem'),
+				).toBe('{{ $json.foo.bar[0].baz }}');
+			});
+
+			it('should convert previous node correctly, runOnceForAllItems', () => {
+				expect(
+					valueToInsert(
+						"{{ $('Some Previous Node').item.json.foo.bar[0].baz }}",
+						'javaScript',
+						'runOnceForAllItems',
+					),
+				).toBe("{{ $('Some Previous Node').first().json.foo.bar[0].baz }}");
+			});
+
+			it('should convert previous node correctly, runOnceForEachItem', () => {
+				expect(
+					valueToInsert(
+						"{{ $('Some Previous Node').item.json.foo.bar[0].baz }}",
+						'javaScript',
+						'runOnceForEachItem',
+					),
+				).toBe("{{ $('Some Previous Node').item.json.foo.bar[0].baz }}");
+			});
+		});
+
+		describe('Python (Pyodide)', () => {
+			it('should convert input item correctly, runOnceForAllItems', () => {
+				expect(valueToInsert('{{ $json.foo.bar[0].baz }}', 'python', 'runOnceForAllItems')).toBe(
+					'{{ _input.first().json.foo.bar[0].baz }}',
+				);
+			});
+
+			it('should convert input item correctly, runOnceForEachItem', () => {
+				expect(valueToInsert('{{ $json.foo.bar[0].baz }}', 'python', 'runOnceForEachItem')).toBe(
+					'{{ _input.item.json.foo.bar[0].baz }}',
+				);
+			});
+
+			it('should convert previous node correctly, runOnceForAllItems', () => {
+				expect(
+					valueToInsert(
+						"{{ $('Some Previous Node').item.json.foo.bar[0].baz }}",
+						'python',
+						'runOnceForAllItems',
+					),
+				).toBe("{{ _('Some Previous Node').first().json.foo.bar[0].baz }}");
+			});
+
+			it('should convert previous node correctly, runOnceForEachItem', () => {
+				expect(
+					valueToInsert(
+						"{{ $('Some Previous Node').item.json.foo.bar[0].baz }}",
+						'python',
+						'runOnceForEachItem',
+					),
+				).toBe("{{ _('Some Previous Node').item.json.foo.bar[0].baz }}");
+			});
+		});
+
+		describe('Python (Native)', () => {
+			it('should convert input item correctly, runOnceForAllItems', () => {
+				expect(
+					valueToInsert('{{ $json.foo.bar[0].baz }}', 'pythonNative', 'runOnceForAllItems'),
+				).toBe('{{ _items[0]["json"]["foo"]["bar"][0]["baz"] }}');
+			});
+
+			it('should convert input item correctly, runOnceForEachItem', () => {
+				expect(
+					valueToInsert('{{ $json.foo.bar[0].baz }}', 'pythonNative', 'runOnceForEachItem'),
+				).toBe('{{ _item["json"]["foo"]["bar"][0]["baz"] }}');
+			});
+		});
+	});
 });

packages/frontend/editor-ui/src/components/CodeNodeEditor/utils.ts

@@ -3,6 +3,8 @@ import type { Completion } from '@codemirror/autocomplete';
 import type { RangeNode } from './types';
 import { sanitizeHtml } from '@/utils/htmlUtils';
 import type { Node } from 'estree';
+import type { CodeNodeLanguageOption } from './CodeNodeEditor.vue';
+import type { CodeExecutionMode } from 'n8n-workflow';
 
 export function walk<T extends RangeNode>(
 	node: Node | esprima.Program,
@@ -57,3 +59,45 @@ export const addInfoRenderer = (option: Completion): Completion => {
 	}
 	return option;
 };
+
+const DOT_CHAINS = /((?:\.[A-Za-z_$][A-Za-z0-9_$]*)+)/g;
+const DOT_KEY = /\.(?<key>[A-Za-z_$][A-Za-z0-9_$]*)/g;
+
+// Convert dot notation ".a.b.c" chains -> ["a"]["b"]["c"]
+const toBracketNotation = (input: string): string => {
+	return input.replace(DOT_CHAINS, (chain) => chain.replace(DOT_KEY, '["$<key>"]'));
+};
+
+const pythonInsert = (value: string, mode: CodeExecutionMode): string => {
+	const base =
+		mode === 'runOnceForAllItems'
+			? value.replace('$json', '_items[0]["json"]')
+			: value.replace('$json', '_item["json"]');
+
+	return toBracketNotation(base);
+};
+
+const pyodideInsert = (value: string, mode: CodeExecutionMode): string => {
+	return value
+		.replace('$json', mode === 'runOnceForAllItems' ? '_input.first().json' : '_input.item.json')
+		.replace(/\$\((.*)\)\.item/, mode === 'runOnceForAllItems' ? '_($1).first()' : '_($1).item');
+};
+
+const jsInsertForAllItems = (value: string): string => {
+	return value.replace('$json', '$input.first().json').replace(/\$\((.*)\)\.item/, '$($1).first()');
+};
+
+const isPyodide = (language: CodeNodeLanguageOption) => language === 'python';
+const isPython = (language: CodeNodeLanguageOption) => language === 'pythonNative';
+
+export const valueToInsert = (
+	value: string,
+	language: CodeNodeLanguageOption,
+	mode: CodeExecutionMode,
+): string => {
+	if (isPython(language)) return pythonInsert(value, mode);
+	if (isPyodide(language)) return pyodideInsert(value, mode);
+	if (mode === 'runOnceForAllItems') return jsInsertForAllItems(value);
+
+	return value;
+};