Use TS Morph to generate type predicates

code-generation/generate-type-predicates.ts

@@ -0,0 +1,50 @@
+import { InterfaceDeclaration, MethodDeclaration, Project, SyntaxKind } from "ts-morph"
+
+// open a new project with just BrowserTypes as the only source file 
+const project = new Project();
+const sourceFile = project.addSourceFileAtPath("./src/api/BrowserTypes.ts")
+
+//get a list of all interfaces in the file
+const interfaces = sourceFile.getChildrenOfKind(SyntaxKind.InterfaceDeclaration);
+
+// get a list of all conversion functions in the Convert class
+const convert = sourceFile.getClass("Convert");
+const convertFunctions = (convert?.getChildrenOfKind(SyntaxKind.MethodDeclaration) ?? []).filter(func => func.getReturnType().getText() === "string");
+
+// generate a list of Interfaces that have an associated conversion function
+const matchedInterfaces = convertFunctions.map(func => {
+    const valueParameter = func.getParameter("value");
+
+    const matchingInterface = interfaces.find(interfaceNode => {
+        return valueParameter?.getType().getText(valueParameter) === interfaceNode.getName();
+    });
+
+
+    if(matchingInterface != null) {
+        return {func, matchingInterface};
+    }
+
+    return undefined;
+}).filter(((value => value != null) as <T>(value: T | null | undefined) => value is T));
+
+// write a type predicate for each matched interface
+matchedInterfaces.forEach(matched => writePredicate(matched.matchingInterface, matched.func));
+
+
+function writePredicate(matchingInterface: InterfaceDeclaration, func: MethodDeclaration): void{
+    const predicateName = `is${matchingInterface.getName()}`;
+
+    sourceFile.addStatements(`export function ${predicateName}(value: any): value is ${matchingInterface.getName()} {
+    try{
+        Convert.${func.getName()}(value);
+        return true;
+    } catch(e: any){
+        return false; 
+    }
+}`);
+
+}
+
+sourceFile.formatText();
+
+project.saveSync();

code-generation/tsconfig.json

@@ -0,0 +1,37 @@
+{
+    // see https://www.typescriptlang.org/tsconfig to better understand tsconfigs
+   "files": ["generate-type-predicates.ts"],
+    "compilerOptions": {
+    "module": "CommonJS",
+      "lib": ["dom", "esnext"],
+      "importHelpers": true,
+      // output .d.ts declaration files for consumers
+      "declaration": true,
+      "outDir": "dist",
+      // output .js.map sourcemap files for consumers
+      "sourceMap": true,
+      // match output dir to input dir. e.g. dist/index instead of dist/src/index
+      "rootDir": "./",
+      // stricter type-checking for stronger correctness. Recommended by TS
+      "strict": true,
+      // linter checks for common issues
+      "noImplicitReturns": true,
+      "noFallthroughCasesInSwitch": true,
+      // noUnused* overlap with @typescript-eslint/no-unused-vars, can disable if duplicative
+      "noUnusedLocals": true,
+      "noUnusedParameters": true,
+      // use Node's module resolution algorithm, instead of the legacy TS one
+      "moduleResolution": "node",
+      // transpile JSX to React.createElement
+      "jsx": "react",
+      // interop between ESM and CJS modules. Recommended by TS
+      "esModuleInterop": true,
+      // significant perf increase by skipping checking .d.ts files, particularly those in node_modules. Recommended by TS
+      "skipLibCheck": true,
+      // error out if import and file system have a casing mismatch. Recommended by TS
+      "forceConsistentCasingInFileNames": true,
+      // `tsdx build` ignores this option, but it is commonly used when type-checking separately with `tsc`
+      "noEmit": true,
+    }
+  }
+

package.json

@@ -27,7 +27,9 @@
     "prepack": "npm run build",
     "typegen": "node s2tQuicktypeUtil.js schemas/context src/context/ContextTypes.ts",
     "typegen-browser": "node s2tQuicktypeUtil.js schemas/api/api.schema.json schemas/api/common.schema.json schemas/api/appRequest.schema.json schemas/api/agentResponse.schema.json schemas/api/agentEvent.schema.json schemas/api src/api/BrowserTypes.ts",
-    "typegen-bridging": "node s2tQuicktypeUtil.js schemas/api schemas/bridging schemas/context/context.schema.json src/bridging/BridgingTypes.ts"
+    "typegen-bridging": "node s2tQuicktypeUtil.js schemas/api schemas/bridging schemas/context/context.schema.json src/bridging/BridgingTypes.ts",
+    "posttypegen-browser": "npm run generate-type-predicates",
+    "generate-type-predicates": "ts-node code-generation/generate-type-predicates.ts"
   },
   "husky": {
     "hooks": {
@@ -65,6 +67,8 @@
     "rimraf": "^5.0.5",
     "rollup": "4.12.1",
     "ts-jest": "29.1.2",
+    "ts-morph": "^23.0.0",
+    "ts-node": "^10.9.2",
     "tslib": "^2.0.1",
     "typescript": "^4.0.3"
   },