Separate findObjectAt out of findObject to allow searching by position

packages/placeholder-plain/src/findObject.js

@@ -1,5 +1,36 @@
 import getIndexFromRef from './getIndexFromRef';
 
+/**
+ * @typedef {object} FindObjectAtReturnType
+ * @property {Buffer} dictionary
+ * @property {Buffer} stream
+ */
+
+/**
+ * @param {Buffer} pdf
+ * @param {number} position
+ * @returns {FindObjectAtReturnType}
+ */
+export const findObjectAt = (pdf, position) => {
+    let slice = pdf.subarray(position);
+    slice = slice.subarray(0, slice.indexOf('endobj', 'utf8') - 1);
+    // ^ Buffer from the start position until the first endobj (included).
+
+    const dictionary = slice.subarray(
+        slice.indexOf('<<', 'utf8') + 2,
+        slice.indexOf('>>', 'utf8') - 1,
+    );
+    const stream = slice.subarray(
+        slice.indexOf('stream', 'utf8') + 6,
+        slice.indexOf('endstream', 'utf8') - 1,
+    );
+
+    return {
+        dictionary,
+        stream,
+    };
+};
+
 /**
  * @param {Buffer} pdf
  * @param {Map} refTable
@@ -9,13 +40,7 @@ const findObject = (pdf, refTable, ref) => {
     const index = getIndexFromRef(refTable, ref);
 
     const offset = refTable.offsets.get(index);
-    let slice = pdf.slice(offset);
-    slice = slice.slice(0, slice.indexOf('endobj', 'utf8'));
-
-    // FIXME: What if it is a stream?
-    slice = slice.slice(slice.indexOf('<<', 'utf8') + 2);
-    slice = slice.slice(0, slice.lastIndexOf('>>', 'utf8'));
-    return slice;
+    return findObjectAt(pdf, offset).stream;
 };
 
 export default findObject;