add stricter assertion into fill()

seiyab · Sep 13, 2024 · cb708fb · cb708fb
1 parent 84b5a80
commit cb708fb
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Showing 2 changed files with 69 additions and 3 deletions.
diff --git a/src/document/builders.js b/src/document/builders.js
@@ -13,7 +13,11 @@ import {
   DOC_TYPE_LINE_SUFFIX_BOUNDARY,
   DOC_TYPE_TRIM,
 } from "./constants.js";
-import { assertDoc, assertDocArray } from "./utils/assert-doc.js";
+import {
+  assertDoc,
+  assertDocArray,
+  assertDocFill,
+} from "./utils/assert-doc.js";
 
 /**
  * TBD properly tagged union for Doc object type is needed here.
@@ -106,7 +110,7 @@ function conditionalGroup(states, opts) {
  * @returns Doc
  */
 function fill(parts) {
-  assertDocArray(parts);
+  assertDocFill(parts);
 
   return { type: DOC_TYPE_FILL, parts };
 }

diff --git a/src/document/utils/assert-doc.js b/src/document/utils/assert-doc.js
@@ -1,5 +1,15 @@
+import {
+  DOC_TYPE_IF_BREAK,
+  DOC_TYPE_LINE,
+  DOC_TYPE_STRING,
+} from "../constants.js";
+import getDocType from "./get-doc-type.js";
 import traverseDoc from "./traverse-doc.js";
 
+/**
+ * @typedef {import("../builders.js").Doc} Doc
+ */
+
 const checked = process.env.NODE_ENV !== "production" && new WeakSet();
 const noop = () => {};
 const assertDoc =
@@ -34,4 +44,56 @@ const assertDocArray =
         }
       };
 
-export { assertDoc, assertDocArray };
+const assertDocFill =
+  process.env.NODE_ENV === "production"
+    ? noop
+    : /**
+       * @param {Doc[]} parts
+       */
+      function (parts) {
+        assertDocArray(parts);
+        for (const [i, doc] of parts.entries()) {
+          if (i % 2 === 0) {
+            continue;
+          }
+          if (!isValidSeparator(doc)) {
+            const type = getDocType(doc);
+            throw new Error(
+              `Unexpected non-line-break doc at ${i}. Doc type is ${type}.`,
+            );
+          }
+        }
+      };
+
+/**
+ * @param {Doc} doc
+ * @returns {boolean}
+ */
+function isValidSeparator(doc) {
+  let hasLine = false;
+  let hasString = false;
+  traverseDoc(doc, (doc) => {
+    switch (getDocType(doc)) {
+      case DOC_TYPE_LINE:
+        hasLine = true;
+        return;
+      case DOC_TYPE_STRING:
+        hasString = true;
+        return;
+      case DOC_TYPE_IF_BREAK:
+        traverseDoc(doc.breakContents, (doc) => {
+          switch (getDocType(doc)) {
+            case DOC_TYPE_LINE:
+              hasLine = true;
+            // We don't check hasString here
+            // We sometimes need string in breakContents like `ifBreak([`{" "}`, line])`
+          }
+        });
+        return false;
+      default:
+    }
+  });
+  return hasLine && !hasString;
+}
+
+export { assertDoc, assertDocArray, assertDocFill };