Selection Context

Get the selected text along with text before and after the selection
Fra og med 05.03.2025. Se den nyeste version.
Dette script bør ikke installeres direkte. Det er et bibliotek, som andre scripts kan inkludere med metadirektivet // @require https://update.greasyfork.org/scripts/528822/1547803/Selection%20Context.js
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// ==UserScript==
// @name         Selection Context
// @namespace    http://tampermonkey.net/
// @version      0.1.1
// @description  Get the selected text along with text before and after the selection
// @author       RoCry
// @license MIT
// ==/UserScript==

/**
 * Gets the selected text along with text before and after the selection
 * @param {number} tryContextLength - Desired length of context to try to collect (before + after selection)
 * @returns {Object} Object containing selectedText, textBefore, textAfter, and paragraphText
 */
function GetSelectionContext(tryContextLength = 500) {
  const MAX_CONTEXT_LENGTH = 8192; // 8K characters max (reduced from 16K)
  const actualContextLength = Math.min(tryContextLength, MAX_CONTEXT_LENGTH);
  const halfContextLength = Math.floor(actualContextLength / 2);

  const selection = window.getSelection();
  if (!selection || selection.rangeCount === 0 || selection.toString().trim() === '') {
    return { selectedText: null, textBefore: null, textAfter: null, paragraphText: null };
  }

  const selectedText = selection.toString().trim();
  const range = selection.getRangeAt(0);

  // Helper function to get text nodes in document order
  function getTextNodesIn(node) {
    const textNodes = [];
    const walk = document.createTreeWalker(node, NodeFilter.SHOW_TEXT, null, false);
    let currentNode;
    while (currentNode = walk.nextNode()) {
      textNodes.push(currentNode);
    }
    return textNodes;
  }

  // Get all text nodes in document
  const allTextNodes = getTextNodesIn(document.body);

  // Find start and end text nodes of the selection
  const startNode = range.startContainer;
  const endNode = range.endContainer;

  let textBefore = '';
  let textAfter = '';

  // Collect text before the selection
  let beforeIndex = allTextNodes.findIndex(node => node === startNode) - 1;
  let currentLength = 0;

  // First add partial text from the start node itself
  if (startNode.nodeType === Node.TEXT_NODE) {
    textBefore = startNode.textContent.substring(0, range.startOffset) + textBefore;
    currentLength = textBefore.length;
  }

  // Then add text from previous nodes
  while (beforeIndex >= 0 && currentLength < halfContextLength) {
    const node = allTextNodes[beforeIndex];
    const nodeText = node.textContent;

    // Add the entire node's text
    textBefore = nodeText + '\n' + textBefore;
    currentLength += nodeText.length;

    beforeIndex--;
  }

  // If we didn't get enough context, add ellipsis
  if (beforeIndex >= 0) {
    textBefore = '...\n' + textBefore;
  }

  // Collect text after the selection
  let afterIndex = allTextNodes.findIndex(node => node === endNode) + 1;
  currentLength = 0;

  // First add partial text from the end node itself
  if (endNode.nodeType === Node.TEXT_NODE) {
    textAfter += endNode.textContent.substring(range.endOffset);
    currentLength = textAfter.length;
  }

  // Then add text from subsequent nodes
  while (afterIndex < allTextNodes.length && currentLength < halfContextLength) {
    const node = allTextNodes[afterIndex];
    const nodeText = node.textContent;

    // Add the entire node's text
    textAfter += nodeText + '\n';
    currentLength += nodeText.length;

    afterIndex++;
  }

  // If we didn't get all the text, add ellipsis
  if (afterIndex < allTextNodes.length) {
    textAfter += '\n...';
  }

  // Clean up and trim the text
  textBefore = textBefore.trim();
  textAfter = textAfter.trim();

  // Combine everything for paragraph text
  const paragraphText = (textBefore + ' ' + selectedText + ' ' + textAfter).trim();

  return { selectedText, textBefore, textAfter, paragraphText };
}

// Export the function for use in other scripts
if (typeof module !== 'undefined' && module.exports) {
  module.exports = { GetSelectionContext };
} else {
  // For direct browser use
  window.SelectionUtils = window.SelectionUtils || {};
  window.SelectionUtils.GetSelectionContext = GetSelectionContext;
}