Groundwork

Author: benjie

package.json

@@ -3,6 +3,10 @@
   "version": "0.0.0",
   "description": "GraphQL Semantic Output Conversion Kit - converts a cutting edge SDL file that supports semantic nullability into a more traditional SDL file legacy tools can support.",
   "main": "dist/index.js",
+  "bin": {
+    "semantic-to-nullable": "dist/cli/to-nullable.js",
+    "semantic-to-strict": "dist/cli/to-strict.js"
+  },
   "scripts": {
     "test": "node --test"
   },

src/cli.ts

@@ -0,0 +1,92 @@
+import {
+  buildSchema,
+  GraphQLInterfaceType,
+  GraphQLNamedType,
+  GraphQLObjectType,
+  GraphQLSchema,
+  printSchema,
+  validateSchema,
+} from "graphql";
+import type { Maybe } from "graphql/jsutils/Maybe";
+import { readFile, writeFile } from "node:fs/promises";
+import { parseArgs } from "node:util";
+
+export async function main(toStrict = false) {
+  const {
+    values: { input, output },
+  } = parseArgs({
+    options: {
+      input: {
+        type: "string",
+        short: "i",
+      },
+      output: {
+        type: "string",
+        short: "o",
+      },
+    },
+  });
+  if (!input) {
+    throw new Error("Please specify an --input schema");
+  }
+  if (!output) {
+    throw new Error("Please specify an --output location");
+  }
+
+  const sdl = await readFile(input, "utf8");
+  const schema = buildSchema(sdl);
+  const errors = validateSchema(schema);
+  if (errors.length > 0) {
+    console.dir(errors);
+    throw new Error("Invalid schema");
+  }
+
+  const config = schema.toConfig();
+  const convertType = makeConvertType(toStrict);
+  const derivedSchema = new GraphQLSchema({
+    ...config,
+    query: convertType(config.query),
+    mutation: convertType(config.mutation),
+    subscription: convertType(config.subscription),
+  });
+
+  const newSdl = printSchema(derivedSchema);
+
+  await writeFile(output, newSdl + "\n");
+}
+
+function makeConvertType(toStrict: boolean) {
+  const cache = new Map<string, GraphQLNamedType>();
+
+  function convertType(type: null | undefined): null | undefined;
+  function convertType(type: GraphQLObjectType): GraphQLObjectType;
+  function convertType(
+    type: Maybe<GraphQLObjectType>,
+  ): Maybe<GraphQLObjectType>;
+  function convertType(type: GraphQLNamedType): GraphQLNamedType;
+  function convertType(type: GraphQLNamedType | null | undefined) {
+    if (!type) return type;
+    if (cache.has(type.name)) {
+      return cache.get(type.name);
+    }
+    const newType = (() => {
+      if (type instanceof GraphQLObjectType) {
+        const config = type.toConfig();
+        return new GraphQLObjectType({
+          ...config,
+        });
+      } else if (type instanceof GraphQLInterfaceType) {
+        const config = type.toConfig();
+        return new GraphQLInterfaceType({
+          ...config,
+        });
+      } else {
+        return type;
+      }
+    })();
+    cache.set(type.name, newType);
+    return newType;
+  }
+
+  return convertType;
+}

src/cli/to-nullable.ts

@@ -0,0 +1,3 @@
+import { main } from "../cli.js";
+
+main(false);

src/cli/to-strict.ts

@@ -0,0 +1,3 @@
+import { main } from "../cli.js";
+
+main(true);