fix: root mappings (#86)

* feat: add support for root mappings

* feat: add support for root mappings

* feat: add support for root mappings

.eslintignore

@@ -4,5 +4,5 @@ coverage
 test
 commitlint.config.js
 jest.config.ts
-vite.config.ts
+vite.config.mts
 app.ts

commitlint.config.js

@@ -1,3 +1,3 @@
-export default {
+module.exports = {
   extends: ['@commitlint/config-conventional'],
 };

package.json

@@ -5,7 +5,6 @@
   "description": "A library for evaluating JSON template expressions.",
   "main": "build/index.js",
   "types": "build/index.d.ts",
-  "type": "module",
   "keywords": [
     "json",
     "jsonpath",
@@ -25,8 +24,8 @@
   },
   "devDependencies": {
     "@babel/eslint-parser": "^7.19.1",
-    "@commitlint/cli": "^17.4.4",
-    "@commitlint/config-conventional": "^17.4.4",
+    "@commitlint/cli": "^17.8.1",
+    "@commitlint/config-conventional": "^17.8.1",
     "@types/jest": "^29.4.0",
     "@types/mocha": "^10.0.1",
     "@types/node": "^18.14.6",

src/utils/converter.ts

@@ -204,17 +204,28 @@ function processFlatMappingPart(
   return objectExpr.props;
 }
 
+function processFlatMapping(flatMapping, currentOutputPropsAST) {
+  for (let i = 0; i < flatMapping.outputExpr.parts.length; i++) {
+    currentOutputPropsAST = processFlatMappingPart(flatMapping, i, currentOutputPropsAST);
+  }
+}
 /**
  * Convert Flat to Object Mappings
  */
-export function convertToObjectMapping(flatMappingAST: FlatMappingAST[]): ObjectExpression {
+export function convertToObjectMapping(
+  flatMappingASTs: FlatMappingAST[],
+): ObjectExpression | PathExpression {
   const outputAST: ObjectExpression = createObjectExpression();
 
-  for (const flatMapping of flatMappingAST) {
-    let currentOutputPropsAST = outputAST.props;
-    for (let i = 0; i < flatMapping.outputExpr.parts.length; i++) {
-      currentOutputPropsAST = processFlatMappingPart(flatMapping, i, currentOutputPropsAST);
+  for (let i = 0; i < flatMappingASTs.length; i++) {
+    const flatMapping = flatMappingASTs[i];
+    if (flatMapping.outputExpr.parts.length === 0) {
+      if (outputAST.props.length === 0 && i === flatMappingASTs.length - 1) {
+        return flatMapping.inputExpr;
+      }
+      throw new Error(`Invalid output mapping: ${flatMapping.output}`);
     }
+    processFlatMapping(flatMapping, outputAST.props);
   }
 
   return outputAST;

test/scenarios/mappings/data.ts

@@ -64,11 +64,7 @@ const input = {
 };
 export const data: Scenario[] = [
   {
-    containsMappings: true,
-    templatePath: 'all_features.json',
-    options: {
-      defaultPathType: PathType.JSON,
-    },
+    mappingsPath: 'all_features.json',
     input,
     output: {
       events: [
@@ -115,11 +111,8 @@ export const data: Scenario[] = [
     },
   },
   {
-    containsMappings: true,
-    templatePath: 'filters.json',
-    options: {
-      defaultPathType: PathType.JSON,
-    },
+    mappingsPath: 'filters.json',
+
     input,
     output: {
       items: [
@@ -137,11 +130,7 @@ export const data: Scenario[] = [
     },
   },
   {
-    containsMappings: true,
-    templatePath: 'index_mappings.json',
-    options: {
-      defaultPathType: PathType.JSON,
-    },
+    mappingsPath: 'index_mappings.json',
     input,
     output: {
       events: [
@@ -157,27 +146,25 @@ export const data: Scenario[] = [
     },
   },
   {
-    containsMappings: true,
-    templatePath: 'invalid_array_mappings.json',
-    options: {
-      defaultPathType: PathType.JSON,
-    },
+    mappingsPath: 'invalid_array_mappings.json',
     error: 'Failed to process output mapping',
   },
   {
-    containsMappings: true,
-    templatePath: 'invalid_object_mappings.json',
-    options: {
-      defaultPathType: PathType.JSON,
-    },
+    mappingsPath: 'invalid_object_mappings.json',
     error: 'Invalid object mapping',
   },
   {
-    containsMappings: true,
-    templatePath: 'mappings_with_root_fields.json',
-    options: {
-      defaultPathType: PathType.JSON,
-    },
+    description: 'Root mapping is used after other mappings',
+    mappingsPath: 'invalid_root_mapping1.json',
+    error: 'Invalid output mapping',
+  },
+  {
+    description: 'Root mapping is used before other mappings',
+    mappingsPath: 'invalid_root_mapping2.json',
+    error: 'Invalid output mapping',
+  },
+  {
+    mappingsPath: 'mappings_with_root_fields.json',
     input,
     output: {
       items: [
@@ -205,11 +192,7 @@ export const data: Scenario[] = [
     },
   },
   {
-    containsMappings: true,
-    templatePath: 'nested_mappings.json',
-    options: {
-      defaultPathType: PathType.JSON,
-    },
+    mappingsPath: 'nested_mappings.json',
     input,
     output: {
       items: [
@@ -256,11 +239,8 @@ export const data: Scenario[] = [
     },
   },
   {
-    containsMappings: true,
-    templatePath: 'object_mappings.json',
-    options: {
-      defaultPathType: PathType.JSON,
-    },
+    mappingsPath: 'object_mappings.json',
+
     input: {
       traits1: {
         name: 'John Doe',
@@ -291,11 +271,12 @@ export const data: Scenario[] = [
     },
   },
   {
-    containsMappings: true,
-    templatePath: 'transformations.json',
-    options: {
-      defaultPathType: PathType.JSON,
-    },
+    mappingsPath: 'only_root_mapping.json',
+    input: { a: 1 },
+    output: { a: 1 },
+  },
+  {
+    mappingsPath: 'transformations.json',
     input,
     output: {
       items: [

test/scenarios/mappings/invalid_root_mapping1.json

@@ -0,0 +1,10 @@
+[
+  {
+    "input": "$.a",
+    "output": "$.b"
+  },
+  {
+    "input": "$",
+    "output": "$"
+  }
+]

test/scenarios/mappings/invalid_root_mapping2.json

@@ -0,0 +1,10 @@
+[
+  {
+    "input": "$",
+    "output": "$"
+  },
+  {
+    "input": "$.a",
+    "output": "$.b"
+  }
+]

test/scenarios/mappings/only_root_mapping.json

@@ -0,0 +1,6 @@
+[
+  {
+    "input": "$",
+    "output": "$"
+  }
+]

test/types.ts

@@ -4,8 +4,8 @@ export type Scenario = {
   description?: string;
   input?: unknown;
   templatePath?: string;
+  mappingsPath?: string;
   template?: string;
-  containsMappings?: true;
   options?: EngineOptions;
   bindings?: Record<string, unknown> | undefined;
   output?: unknown;
@@ -17,8 +17,8 @@ export namespace Scenario {
     if (scenario.templatePath) {
       return scenario.templatePath;
     }
-    if (scenario.containsMappings) {
-      return 'mappings.json';
+    if (scenario.mappingsPath) {
+      return scenario.mappingsPath;
     }
     return 'template.jt';
   }

test/utils/scenario.ts

@@ -7,13 +7,20 @@ function getTemplate(scenarioDir: string, scenario: Scenario): string {
   const templatePath = join(scenarioDir, Scenario.getTemplatePath(scenario));
   return readFileSync(templatePath, 'utf-8');
 }
+
+function getDefaultPathType(scenario: Scenario): PathType {
+  return scenario.mappingsPath ? PathType.JSON : PathType.SIMPLE;
+}
+
 function initializeScenario(scenarioDir: string, scenario: Scenario) {
   scenario.options = scenario.options || {};
-  scenario.options.defaultPathType = scenario.options.defaultPathType || PathType.SIMPLE;
+  scenario.options.defaultPathType =
+    scenario.options.defaultPathType || getDefaultPathType(scenario);
   let template = scenario.template ?? getTemplate(scenarioDir, scenario);
-  if (scenario.containsMappings) {
+  if (scenario.mappingsPath) {
     template = JsonTemplateEngine.convertMappingsToTemplate(
       JSON.parse(template) as FlatMappingPaths[],
+      scenario.options,
     );
   }
   scenario.template = JsonTemplateEngine.reverseTranslate(
@@ -24,7 +31,7 @@ function initializeScenario(scenarioDir: string, scenario: Scenario) {
 
 export function evaluateScenario(scenarioDir: string, scenario: Scenario): any {
   initializeScenario(scenarioDir, scenario);
-  if (scenario.containsMappings) {
+  if (scenario.mappingsPath) {
     return JsonTemplateEngine.evaluateAsSync(
       scenario.template,
       scenario.options,

tsconfig.json

@@ -11,7 +11,7 @@
     // "disableReferencedProjectLoad": true,             /* Reduce the number of projects loaded automatically by TypeScript. */
 
     /* Language and Environment */
-    "target": "es2021" /* Set the JavaScript language version for emitted JavaScript and include compatible library declarations. */,
+    "target": "ESNext" /* Set the JavaScript language version for emitted JavaScript and include compatible library declarations. */,
     // "lib": [],                                        /* Specify a set of bundled library declaration files that describe the target runtime environment. */
     // "jsx": "preserve",                                /* Specify what JSX code is generated. */
     "experimentalDecorators": true /* Enable experimental support for TC39 stage 2 draft decorators. */,
@@ -25,7 +25,7 @@
     // "moduleDetection": "auto",                        /* Control what method is used to detect module-format JS files. */
 
     /* Modules */
-    "module": "commonjs" /* Specify what module code is generated. */,
+    "module": "ESNext" /* Specify what module code is generated. */,
     "rootDir": "./src" /* Specify the root folder within your source files. */,
     "moduleResolution": "node" /* Specify how TypeScript looks up a file from a given module specifier. */,
     "baseUrl": "./" /* Specify the base directory to resolve non-relative module names. */,

vite.config.ts → vite.config.mts

@@ -7,7 +7,7 @@ export default defineConfig({
     lib: {
       entry: resolve(__dirname, 'src/index.ts'),
       formats: ['es'],
-      fileName: 'json-template',
+      fileName: () => 'json-template.js',
     },
     outDir: 'build',
   },