documenso/packages/signing/PDFArrayCustom.js

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;