✨🚧 signDocument using node signpdf and custom placeholder insert

packages/signing/PDFArrayCustom.js

@@ -0,0 +1,55 @@
+const { PDFArray, CharCodes } = require("pdf-lib");
+
+/**
+ * Extends PDFArray class in order to make ByteRange look like this:
+ *  /ByteRange [0 /********** /********** /**********]
+ * Not this:
+ *  /ByteRange [ 0 /********** /********** /********** ]
+ */
+class PDFArrayCustom extends PDFArray {
+  static withContext(context) {
+    return new PDFArrayCustom(context);
+  }
+
+  clone(context) {
+    const clone = PDFArrayCustom.withContext(context || this.context);
+    for (let idx = 0, len = this.size(); idx < len; idx++) {
+      clone.push(this.array[idx]);
+    }
+    return clone;
+  }
+
+  toString() {
+    let arrayString = "[";
+    for (let idx = 0, len = this.size(); idx < len; idx++) {
+      arrayString += this.get(idx).toString();
+      if (idx < len - 1) arrayString += " ";
+    }
+    arrayString += "]";
+    return arrayString;
+  }
+
+  sizeInBytes() {
+    let size = 2;
+    for (let idx = 0, len = this.size(); idx < len; idx++) {
+      size += this.get(idx).sizeInBytes();
+      if (idx < len - 1) size += 1;
+    }
+    return size;
+  }
+
+  copyBytesInto(buffer, offset) {
+    const initialOffset = offset;
+
+    buffer[offset++] = CharCodes.LeftSquareBracket;
+    for (let idx = 0, len = this.size(); idx < len; idx++) {
+      offset += this.get(idx).copyBytesInto(buffer, offset);
+      if (idx < len - 1) buffer[offset++] = CharCodes.Space;
+    }
+    buffer[offset++] = CharCodes.RightSquareBracket;
+
+    return offset - initialOffset;
+  }
+}
+
+module.exports = PDFArrayCustom;