Initial commit

Author: ffflorian

.gitignore

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+node_modules
+generated
+yarn-error.log

LICENSE

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+<img src="images/header.svg" height="250px" />
+
+# Code Generation With TypeScript
+
+These are the slides and the code examples for our [Berlin.JS](https://berlinjs.org) talk "Code Generation With TypeScript".
+
+## Slides
+
+- see [Code Generation with TypeScript.pdf](./slides/Code%20Generation%20with%20TypeScript.pdf)
+
+## Code Examples
+
+- see [code-examples](./code-examples)
+
+## Authors
+
+- Benny Neugebauer ([Twitter](https://twitter.com/bennycode), [GitHub](https://github.com/bennyn))
+- Florian Keller ([GitHub](https://github.com/ffflorian))

README.md

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+registry=https://registry.npmjs.org/
+save-exact=true

code-examples/.npmrc

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+--registry "https://registry.npmjs.org"

code-examples/.yarnrc

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+# Code Generation With TypeScript
+
+These are the code examples for our talk "Code Generation With TypeScript".
+
+## Prerequisites
+
+- [Node.js](https://nodejs.org) >= 12.4.0
+- [yarn](https://yarnpkg.com)
+
+## Installation
+
+- Run `yarn`
+
+## Usage
+
+- Run `yarn start:ast` to generate code with a simple AST
+- Run `yarn start:hbs` to generate code with Handlebars
+- Run `yarn start:ts` to generate code with TypeScript

code-examples/LICENSE

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+{
+  "dependencies": {
+    "@types/node": "13.1.7",
+    "handlebars": "4.7.2",
+    "typescript": "3.7.4"
+  },
+  "devDependencies": {
+    "@ffflorian/prettier-config": "0.0.6",
+    "prettier": "1.19.1",
+    "ts-node": "8.6.2"
+  },
+  "engines": {
+    "node": ">= 12.4.0"
+  },
+  "license": "GPL-3.0",
+  "main": "index.js",
+  "name": "code-generation",
+  "prettier": "@ffflorian/prettier-config",
+  "private": true,
+  "scripts": {
+    "fix": "yarn prettier --write",
+    "prettier": "prettier \"src/*.{json,ts}\"",
+    "start:ast": "ts-node src/generate-from-ast.ts",
+    "start:hbs": "ts-node src/build-with-handlebars.ts",
+    "start:ts": "ts-node src/build-with-ts.ts",
+    "test": "yarn prettier --list-different && tsc --noEmit"
+  },
+  "version": "1.0.0"
+}

code-examples/README.md

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+import Handlebars from 'handlebars';
+
+import jsonContent from './swagger.json';
+import {writeFile} from './fileUtil';
+
+type InterfaceDeclaration = {isRequired: boolean; name: string; type: string};
+type PropertiesSchema = Record<string, {type: string} | undefined>;
+
+interface TypeDeclaration {
+  basicType: string;
+  name: string;
+  properties: InterfaceDeclaration[];
+}
+
+const handlebarsTemplate = `{{{basicType}}} {{{name}}} {
+  {{#each properties}}
+    {{{this.name}}}{{#if this.isRequired}}{{else}}?{{/if}}: {{{this.type}}};
+  {{/each}}
+}`;
+
+function mapSwaggerTypeToKeyword(type: string): string {
+  switch (type) {
+    case 'integer':
+    case 'number':
+      return 'number';
+    case 'string':
+      return 'string';
+    default:
+      return 'unknown';
+  }
+}
+
+function createDeclaration(
+  declarationName: string,
+  propertiesSchema: PropertiesSchema,
+  requiredProperties: string[]
+): TypeDeclaration {
+  const mappedProperties = Object.entries(propertiesSchema).map(([propertyName, propertySchema]) => {
+    const typeKeyword = mapSwaggerTypeToKeyword(propertySchema!.type);
+    const isRequired = requiredProperties.includes(propertyName);
+    return {name: propertyName, isRequired, type: typeKeyword};
+  });
+
+  return {
+    basicType: 'interface',
+    name: declarationName,
+    properties: mappedProperties,
+  };
+}
+
+function saveDeclarations(declarations: TypeDeclaration[]): Promise<void> {
+  const fileName = 'interfaces-hbs.ts';
+
+  const sourceCode = declarations
+    .map(declaration => {
+      const templateDelegate = Handlebars.compile(handlebarsTemplate);
+      return templateDelegate(declaration);
+    })
+    .join('\n\n');
+
+  return writeFile(fileName, sourceCode);
+}
+
+const declarations = Object.entries(jsonContent.definitions).map(([definitionName, definitionSchema]) =>
+  createDeclaration(definitionName, definitionSchema.properties, definitionSchema.required)
+);
+
+saveDeclarations(declarations).catch(error => console.error(error));

code-examples/package.json

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+import ts from 'typescript';
+
+import jsonContent from './swagger.json';
+import {writeFile} from './fileUtil';
+
+type PropertiesSchema = Record<string, {type: string} | undefined>;
+
+function mapSwaggerTypeToKeyword(swaggerType: string): number {
+  switch (swaggerType) {
+    case 'integer':
+    case 'number':
+      return ts.SyntaxKind.NumberKeyword;
+    case 'string':
+      return ts.SyntaxKind.StringKeyword;
+    default:
+      return ts.SyntaxKind.UnknownKeyword;
+  }
+}
+
+function createDeclaration(
+  declarationName: string,
+  propertiesSchema: PropertiesSchema,
+  requiredProperties: string[] = []
+): ts.InterfaceDeclaration {
+  const mappedProperties = Object.entries(propertiesSchema).map(([propertyName, propertySchema]) => {
+    // e.g. SyntaxKind.StringKeyword
+    const typeSyntaxKind = mapSwaggerTypeToKeyword(propertySchema!.type);
+
+    // e.g. 'string'
+    const typeKeyword = ts.createKeywordTypeNode(typeSyntaxKind);
+
+    // e.g. '?'
+    const questionMarkToken = requiredProperties.includes(propertyName)
+      ? undefined
+      : ts.createToken(ts.SyntaxKind.QuestionToken);
+
+    return ts.createPropertySignature(
+      undefined,           // readonly?
+      propertyName,        // property name
+      questionMarkToken,   // required?
+      typeKeyword,         // property type
+      undefined,           // expression, e.g. '++'
+    );
+  });
+
+  return ts.createInterfaceDeclaration(
+    undefined,             // private?
+    undefined,             // readonly?
+    declarationName,       // interface name
+    undefined,             // generics?
+    undefined,             // extends?
+    mappedProperties,      // properties
+  );
+}
+
+function saveDeclarations(declarations: ts.InterfaceDeclaration[]): Promise<void> {
+  const fileName = 'interfaces-ts.ts';
+
+  const sourceFile = ts.createSourceFile(fileName, '', ts.ScriptTarget.ESNext);
+  const sourceCode = declarations
+    .map(declaration => ts.createPrinter().printNode(ts.EmitHint.Unspecified, declaration, sourceFile))
+    .join('\n\n');
+
+  return writeFile(fileName, sourceCode);
+}
+
+const declarations = Object.entries(jsonContent.definitions).map(([definitionName, definitionSchema]) =>
+  createDeclaration(definitionName, definitionSchema.properties, definitionSchema.required)
+);
+
+saveDeclarations(declarations).catch(error => console.error(error));

code-examples/src/build-with-handlebars.ts

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+import {promises as fs} from 'fs';
+import * as path from 'path';
+
+export async function writeFile(fileName: string, content: string): Promise<void> {
+  const dirName = path.join(__dirname, '../generated');
+
+  try {
+    await fs.mkdir(dirName);
+  } catch (error) {}
+
+  await fs.writeFile(path.join(dirName, fileName), content, 'utf-8');
+}

code-examples/src/build-with-ts.ts

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+import ts from 'typescript';
+
+const nodes: any = {}; // add your AST here
+
+const sourceFile = ts.createSourceFile('', '', ts.ScriptTarget.ESNext);
+const printer = ts.createPrinter();
+const sourceCode = printer.printNode(ts.EmitHint.Unspecified, nodes, sourceFile);
+
+console.log(sourceCode);

code-examples/src/fileUtil.ts

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+{
+  "basePath": "/",
+  "definitions": {
+    "Pet": {
+      "properties": {
+        "food": {
+          "type": "string"
+        },
+        "id": {
+          "type": "number"
+        },
+        "name": {
+          "type": "string"
+        }
+      },
+      "required": ["id", "name"],
+      "type": "object"
+    },
+    "Home": {
+      "properties": {
+        "costs": {
+          "type": "number"
+        },
+        "rooms": {
+          "type": "number"
+        },
+        "id": {
+          "type": "number"
+        }
+      },
+      "required": ["id", "name"],
+      "type": "object"
+    }
+  },
+  "info": {
+    "description": "This is a sample server Petstore server.",
+    "title": "Swagger Petstore",
+    "version": "1.0.3"
+  },
+  "paths": {
+    "/pet/{petId}": {
+      "get": {
+        "parameters": [
+          {
+            "description": "ID of pet to return",
+            "in": "path",
+            "name": "petId",
+            "required": true,
+            "type": "integer"
+          }
+        ],
+        "produces": ["application/json"],
+        "responses": {
+          "200": {
+            "description": "successful operation",
+            "schema": {
+              "$ref": "#/definitions/Pet"
+            }
+          }
+        }
+      }
+    }
+  },
+  "schemes": ["https"],
+  "swagger": "2.0",
+  "tags": []
+}

code-examples/src/generate-from-ast.ts

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+{
+  "compilerOptions": {
+    "alwaysStrict": true,
+    "declaration": true,
+    "esModuleInterop": true,
+    "forceConsistentCasingInFileNames": true,
+    "lib": ["es2018"],
+    "module": "commonjs",
+    "moduleResolution": "node",
+    "noEmitOnError": true,
+    "noImplicitAny": true,
+    "noImplicitReturns": true,
+    "noImplicitThis": true,
+    "noUnusedLocals": true,
+    "outDir": "dist",
+    "resolveJsonModule": true,
+    "rootDir": "src",
+    "sourceMap": true,
+    "strict": true,
+    "strictFunctionTypes": true,
+    "target": "es6"
+  },
+  "exclude": ["node_modules", "generated"]
+}