feat: add generate example preset for JS (#629)

docs/languages/JavaScript.md

@@ -7,6 +7,7 @@ There are special use-cases that each language supports; this document pertains
 
 - [Rendering complete models to a specific module system](#rendering-complete-models-to-a-specific-module-system)
 - [Generate un/marshal functions for classes](#generate-unmarshal-functions-for-classes)
+- [Generate example data function](#generate-example-data-function)
 
 <!-- tocstop -->
 
@@ -25,3 +26,9 @@ Sometimes you want to use the models for data transfers, and while most cases wo
 Here, this can be done by including the preset `JS_COMMON_PRESET` using the option `marshalling`.
 
 Check out this [example out for a live demonstration](../../examples/javascript-generate-marshalling).
+
+## Generate example data function
+
+Generate example instance of the data model including the preset `JS_COMMON_PRESET` using the option `example`.
+
+Check out this [example out for a live demonstration](../../examples/javascript-generate-example).

examples/README.md

@@ -26,6 +26,7 @@ This directory contains a series of self-contained examples that you can use as
 - [javascript-use-esm](./javascript-use-esm) - A basic example that generate the models to use ESM module system.
 - [javascript-use-cjs](./javascript-use-cjs) - A basic example that generate the models to use CJS module system.
 - [javascript-generate-marshalling](./javascript-generate-marshalling) - A basic example of how to use the un/marshalling functionality of the javascript class.
+- [javascript-generate-example](./javascript-generate-example) - A basic example of how to use Modelina and output a JavaScript class with an example function.
 - [generate-java-models](./generate-java-models) - A basic example to generate Java data models.
 - [generate-go-models](./generate-go-models) - A basic example to generate Go data models
 - [include-custom-function](./include-custom-function) - A basic example where a custom function is included.

examples/javascript-generate-example/README.md

@@ -0,0 +1,18 @@
+# JavaScript Data Models with example function
+
+A basic example of how to use Modelina and output a TypeScript class with an example function.
+
+
+## How to run this example
+
+Run this example using:
+
+```sh
+npm i && npm run start
+```
+
+If you are on Windows, use the `start:windows` script instead:
+
+```sh
+npm i && npm run start:windows
+```

examples/javascript-generate-example/__snapshots__/index.spec.ts.snap

@@ -0,0 +1,24 @@
+// Jest Snapshot v1, https://goo.gl/fbAQLP
+
+exports[`Should be able to generate ts data model with example function and should log expected output to console 1`] = `
+Array [
+  "class Root {
+  email;
+
+  constructor(input) {
+    if (input.hasOwnProperty('email')) {
+      this.email = input.email;
+    }
+  }
+
+  get email() { return this.email; }
+  set email(email) { this.email = email; }
+
+  example(){
+    const instance = new Root({});
+    instance.email = \\"string\\";
+    return instance;
+  }
+}",
+]
+`;

examples/javascript-generate-example/index.spec.ts

@@ -0,0 +1,14 @@
+const spy = jest.spyOn(global.console, 'log').mockImplementation(() => { return; });
+import { generate } from './index';
+
+describe('Should be able to generate ts data model with example function', () => {
+  afterAll(() => {
+    jest.restoreAllMocks();
+  });
+  test('and should log expected output to console', async () => {
+    await generate();
+    //Generate is called 2x, so even though we expect 1 model, we double it
+    expect(spy.mock.calls.length).toEqual(2);
+    expect(spy.mock.calls[1]).toMatchSnapshot();
+  });
+});

examples/javascript-generate-example/index.ts

@@ -0,0 +1,32 @@
+import { JavaScriptGenerator } from '../../src';
+import { JS_COMMON_PRESET } from '../../src';
+
+const generator = new JavaScriptGenerator({
+  presets: [
+    {
+      preset: JS_COMMON_PRESET,
+      options: {
+        example: true
+      }
+    }
+  ]
+});
+const jsonSchemaDraft7 = {
+  $schema: 'http://json-schema.org/draft-07/schema#',
+  type: 'object',
+  additionalProperties: false,
+  properties: {
+    email: {
+      type: 'string',
+      format: 'email'
+    }
+  }
+};
+
+export async function generate(): Promise<void> {
+  const models = await generator.generate(jsonSchemaDraft7);
+  for (const model of models) {
+    console.log(model.result);
+  }
+}
+generate();

examples/javascript-generate-example/package.json

@@ -0,0 +1,12 @@
+{
+  "config": {
+    "example_name": "javascript-generate-example"
+  },
+  "scripts": {
+    "install": "cd ../.. && npm i",
+    "start": "../../node_modules/.bin/ts-node --cwd ../../ ./examples/$npm_package_config_example_name/index.ts",
+    "start:windows": "..\\..\\node_modules\\.bin\\ts-node --cwd ..\\..\\ .\\examples\\%npm_package_config_example_name%\\index.ts",
+    "test": "../../node_modules/.bin/jest --config=../../jest.config.js ./examples/$npm_package_config_example_name/index.spec.ts",
+    "test:windows": "..\\..\\node_modules\\.bin\\jest --config=..\\..\\jest.config.js examples/%npm_package_config_example_name%/index.spec.ts"
+  }
+}

src/generators/javascript/presets/CommonPreset.ts

@@ -2,9 +2,11 @@ import { JavaScriptRenderer } from '../JavaScriptRenderer';
 import { JavaScriptPreset } from '../JavaScriptPreset';
 import { getUniquePropertyName, DefaultPropertyNames, TypeHelpers, ModelKind } from '../../../helpers';
 import { CommonInputModel, CommonModel } from '../../../models';
+import renderExampleFunction from './utils/ExampleFunction';
 
 export interface JavaScriptCommonPresetOptions {
   marshalling: boolean;
+  example: boolean;
 }
 
 function realizePropertyFactory(prop: string) {
@@ -200,7 +202,9 @@ export const JS_COMMON_PRESET: JavaScriptPreset = {
         blocks.push(renderMarshal({ renderer, model, inputModel }));
         blocks.push(renderUnmarshal({ renderer, model, inputModel }));
       }
-
+      if (options.example === true) {
+        blocks.push(renderExampleFunction({ renderer, model }));
+      }
       return renderer.renderBlock([content, ...blocks], 2);
     },
   }

src/generators/javascript/presets/utils/ExampleFunction.ts

@@ -0,0 +1,66 @@
+import { JavaScriptRenderer } from '../../JavaScriptRenderer';
+import { CommonModel } from '../../../../models';
+
+export function renderValueFromModel(model: CommonModel, renderer: JavaScriptRenderer): string | undefined {
+  if (model.$ref !== undefined) {
+    return `${renderer.nameType(model.$ref)}.example()`;
+  }
+  if (Array.isArray(model.type)) {
+    if (model.type.length > 0) {
+      return renderValueFromType(model.type[0], model, renderer);
+    }
+    return undefined;
+  }
+  return renderValueFromType(model.type, model, renderer);
+}
+
+export function renderValueFromType(modelType: string | undefined, model: CommonModel, renderer: JavaScriptRenderer): string | undefined {
+  if (modelType === undefined) {
+    return undefined;
+  }
+  switch (modelType) {
+  case 'string':
+    return '"string"';
+  case 'integer':
+  case 'number':
+    return '0';
+  case 'boolean':
+    return 'true';
+  case 'array': {
+    if (model.items === undefined) {
+      return '[]';
+    }
+    if (Array.isArray(model.items)) {
+      const arrayValues = model.items.map((item) => {
+        return renderValueFromModel(item, renderer);
+      });
+      return `[${arrayValues.join(', ')}]`;
+    }
+    const arrayType = renderValueFromModel(model.items, renderer);
+    return `[${arrayType}]`;
+  }
+  }
+  return undefined;
+}
+
+export default function renderExampleFunction({ renderer, model }: {
+    renderer: JavaScriptRenderer,
+    model: CommonModel
+}): string {
+  const properties = model.properties || {};
+  const setProperties = [];
+  for (const [propertyName, property] of Object.entries(properties)) {
+    const formattedPropertyName = renderer.nameProperty(propertyName, property);
+    const potentialRenderedValue = renderValueFromModel(property, renderer);
+    if (potentialRenderedValue === undefined) {
+      continue;
+    }
+    setProperties.push(`  instance.${formattedPropertyName} = ${potentialRenderedValue};`);
+  }
+  const formattedModelName = renderer.nameType(model.$id);
+  return `example(){
+  const instance = new ${formattedModelName}({});
+${(setProperties.join('\n'))}
+  return instance;
+}`;
+}

test/generators/javascript/preset/ExamplePreset.spec.ts

@@ -0,0 +1,40 @@
+import { JavaScriptGenerator, JS_COMMON_PRESET } from '../../../../src/generators';
+const doc = {
+  $id: 'Test',
+  type: 'object',
+  additionalProperties: true,
+  required: ['string prop'],
+  properties: {
+    'string prop': { type: 'string' },
+    numberProp: { type: 'number' },
+    objectProp: { type: 'object', $id: 'NestedTest', properties: { stringProp: { type: 'string' } } }
+  },
+  patternProperties: {
+    '^S(.?)test': {
+      type: 'string'
+    }
+  },
+};
+describe('Example function generation', () => {
+  test('should render example function for model', async () => {
+    const generator = new JavaScriptGenerator({
+      presets: [
+        {
+          preset: JS_COMMON_PRESET,
+          options: {
+            example: true
+          }
+        }
+      ]
+    });
+    const inputModel = await generator.process(doc);
+    const testModel = inputModel.models['Test'];
+    const nestedTestModel = inputModel.models['NestedTest'];
+
+    const testClass = await generator.renderClass(testModel, inputModel);
+    const nestedTestClass = await generator.renderClass(nestedTestModel, inputModel);
+
+    expect(testClass.result).toMatchSnapshot();
+    expect(nestedTestClass.result).toMatchSnapshot();
+  });
+});

test/generators/javascript/preset/__snapshots__/ExamplePreset.spec.ts.snap

@@ -0,0 +1,69 @@
+// Jest Snapshot v1, https://goo.gl/fbAQLP
+
+exports[`Example function generation should render example function for model 1`] = `
+"class Test {
+  stringProp;
+  numberProp;
+  objectProp;
+  additionalProperties;
+  sTestPatternProperties;
+
+  constructor(input) {
+    this.stringProp = input.stringProp;
+    if (input.hasOwnProperty('numberProp')) {
+      this.numberProp = input.numberProp;
+    }
+    if (input.hasOwnProperty('objectProp')) {
+      this.objectProp = input.objectProp;
+    }
+  }
+
+  get stringProp() { return this.stringProp; }
+  set stringProp(stringProp) { this.stringProp = stringProp; }
+
+  get numberProp() { return this.numberProp; }
+  set numberProp(numberProp) { this.numberProp = numberProp; }
+
+  get objectProp() { return this.objectProp; }
+  set objectProp(objectProp) { this.objectProp = objectProp; }
+
+  get additionalProperties() { return this.additionalProperties; }
+  set additionalProperties(additionalProperties) { this.additionalProperties = additionalProperties; }
+
+  get sTestPatternProperties() { return this.sTestPatternProperties; }
+  set sTestPatternProperties(sTestPatternProperties) { this.sTestPatternProperties = sTestPatternProperties; }
+
+  example(){
+    const instance = new Test({});
+    instance.stringProp = \\"string\\";
+    instance.numberProp = 0;
+    instance.objectProp = NestedTest.example();
+    return instance;
+  }
+}"
+`;
+
+exports[`Example function generation should render example function for model 2`] = `
+"class NestedTest {
+  stringProp;
+  additionalProperties;
+
+  constructor(input) {
+    if (input.hasOwnProperty('stringProp')) {
+      this.stringProp = input.stringProp;
+    }
+  }
+
+  get stringProp() { return this.stringProp; }
+  set stringProp(stringProp) { this.stringProp = stringProp; }
+
+  get additionalProperties() { return this.additionalProperties; }
+  set additionalProperties(additionalProperties) { this.additionalProperties = additionalProperties; }
+
+  example(){
+    const instance = new NestedTest({});
+    instance.stringProp = \\"string\\";
+    return instance;
+  }
+}"
+`;