1 files changed, 69 insertions, 0 deletions
diff --git a/scripts/frontend/graphql_possible_types_extraction.js b/scripts/frontend/graphql_possible_types_extraction.js
new file mode 100755
index 00000000000..61f783086e7
--- /dev/null
+++ b/scripts/frontend/graphql_possible_types_extraction.js
@@ -0,0 +1,69 @@
+#!/usr/bin/env node
+
+const fs = require('fs/promises');
+const path = require('path');
+const assert = require('assert');
+
+const ROOT_DIR = path.join(__dirname, '../../');
+const GRAPHQL_SCHEMA = path.join(ROOT_DIR, 'tmp/tests/graphql/gitlab_schema.json');
+const POSSIBLE_TYPES_REL = 'app/assets/javascripts/graphql_shared/possible_types.json';
+const POSSIBLE_TYPES = path.join(ROOT_DIR, POSSIBLE_TYPES_REL);
+
+function extractTypes(schema) {
+  return Object.fromEntries(
+    // eslint-disable-next-line no-underscore-dangle
+    schema.data.__schema.types
+      .filter((type) => type.possibleTypes)
+      .map(({ name, possibleTypes }) => [name, possibleTypes.map((subtype) => subtype.name)]),
+  );
+}
+
+async function main() {
+  let schema;
+  try {
+    schema = JSON.parse(await fs.readFile(GRAPHQL_SCHEMA, 'utf-8'));
+  } catch (e) {
+    console.error(
+      'Could not read the GraphQL Schema, make sure to run: bundle exec rake gitlab:graphql:schema:dump',
+    );
+    throw e;
+  }
+
+  const possibleTypes = extractTypes(schema);
+
+  if (process.argv.includes('--check')) {
+    const previousTypes = JSON.parse(await fs.readFile(POSSIBLE_TYPES, 'utf-8'));
+
+    assert.deepStrictEqual(
+      previousTypes,
+      possibleTypes,
+      `
+${POSSIBLE_TYPES_REL} needs to be regenerated, please run:
+    node scripts/frontend/graphql_possible_types_extraction.js --write
+and commit the changes!
+    `,
+    );
+    return;
+  }
+
+  if (process.argv.includes('--write')) {
+    const stringifiedPossibleTypes = JSON.stringify(possibleTypes, null, 2);
+    await fs.writeFile(POSSIBLE_TYPES, `${stringifiedPossibleTypes}\n`);
+    console.log(`Successfully updated ${POSSIBLE_TYPES_REL}`);
+    return;
+  }
+
+  throw new Error(`
+ERROR: Please use the script correctly:
+Usage: graphql_possible_types_extraction [options]
+
+Options:
+  --check  Check whether there are new Interface or Union types
+  --write  Generate new possible types
+  `);
+}
+
+main().catch((error) => {
+  console.warn(error.message);
+  process.exitCode = 1;
+});