1 files changed, 134 insertions, 0 deletions
diff --git a/src/write/validate-writes.js b/src/write/validate-writes.js
new file mode 100644
index 00000000..5d61d0e7
--- /dev/null
+++ b/src/write/validate-writes.js
@@ -0,0 +1,134 @@
+import {logError} from '../util/cli.js';
+
+function validateWritePath(path, urlGroup) {
+  if (!Array.isArray(path)) {
+    return {error: `Expected array, got ${path}`};
+  }
+
+  const {paths} = urlGroup;
+
+  const definedKeys = Object.keys(paths);
+  const specifiedKey = path[0];
+
+  if (!definedKeys.includes(specifiedKey)) {
+    return {error: `Specified key ${specifiedKey} isn't defined`};
+  }
+
+  const expectedArgs = paths[specifiedKey].match(/<>/g)?.length ?? 0;
+  const specifiedArgs = path.length - 1;
+
+  if (specifiedArgs !== expectedArgs) {
+    return {
+      error: `Expected ${expectedArgs} arguments, got ${specifiedArgs}`,
+    };
+  }
+
+  return {success: true};
+}
+
+function validateWriteObject(obj, {
+  urlSpec,
+}) {
+  if (typeof obj !== 'object') {
+    return {error: `Expected object, got ${typeof obj}`};
+  }
+
+  if (typeof obj.type !== 'string') {
+    return {error: `Expected type to be string, got ${obj.type}`};
+  }
+
+  switch (obj.type) {
+    case 'legacy': {
+      if (typeof obj.write !== 'function') {
+        return {error: `Expected write to be string, got ${obj.write}`};
+      }
+
+      break;
+    }
+
+    case 'page': {
+      const path = validateWritePath(obj.path, urlSpec.localized);
+      if (path.error) {
+        return {error: `Path validation failed: ${path.error}`};
+      }
+
+      if (typeof obj.page !== 'function') {
+        return {error: `Expected page to be function, got ${obj.content}`};
+      }
+
+      break;
+    }
+
+    case 'data': {
+      const path = validateWritePath(obj.path, urlSpec.data);
+      if (path.error) {
+        return {error: `Path validation failed: ${path.error}`};
+      }
+
+      if (typeof obj.data !== 'function') {
+        return {error: `Expected data to be function, got ${obj.data}`};
+      }
+
+      break;
+    }
+
+    case 'redirect': {
+      const fromPath = validateWritePath(obj.fromPath, urlSpec.localized);
+      if (fromPath.error) {
+        return {
+          error: `Path (fromPath) validation failed: ${fromPath.error}`,
+        };
+      }
+
+      const toPath = validateWritePath(obj.toPath, urlSpec.localized);
+      if (toPath.error) {
+        return {error: `Path (toPath) validation failed: ${toPath.error}`};
+      }
+
+      if (typeof obj.title !== 'function') {
+        return {error: `Expected title to be function, got ${obj.title}`};
+      }
+
+      break;
+    }
+
+    default: {
+      return {error: `Unknown type: ${obj.type}`};
+    }
+  }
+
+  return {success: true};
+}
+
+export function validateWrites(writes, {
+  functionName,
+  urlSpec,
+}) {
+  // Do a quick valid8tion! If one of the writeThingPages functions go
+  // wrong, this will stall out early and tell us which did.
+
+  if (!Array.isArray(writes)) {
+    logError`${functionName} didn't return an array!`;
+    return false;
+  }
+
+  if (!(
+    writes.every((obj) => typeof obj === 'object') &&
+    writes.every((obj) => {
+      const result = validateWriteObject(obj, {
+        urlSpec,
+      });
+      if (result.error) {
+        logError`Validating write object failed: ${result.error}`;
+        return false;
+      } else {
+        return true;
+      }
+    })
+  )) {
+    logError`${functionName} returned invalid entries!`;
+    return false;
+  }
+
+  return true;
+}