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Selection Context

Get the selected text along with text before and after the selection

当前为 2025-03-05 提交的版本，查看 最新版本。

此脚本不应直接安装。它是供其他脚本使用的外部库，要使用该库请加入元指令 // @require https://update.cn-greasyfork.org/scripts/528822/1547803/Selection%20Context.js 

  1. // ==UserScript==
  2. // @name         Selection Context
  3. // @namespace    http://tampermonkey.net/
  4. // @version      0.1.1
  5. // @description  Get the selected text along with text before and after the selection
  6. // @author       RoCry
  7. // @license MIT
  8. // ==/UserScript==
  9.  
  10. /**
  11.  * Gets the selected text along with text before and after the selection
  12.  * @param {number} tryContextLength - Desired length of context to try to collect (before + after selection)
  13.  * @returns {Object} Object containing selectedText, textBefore, textAfter, and paragraphText
  14.  */
  15. function GetSelectionContext(tryContextLength = 500) {
  16.   const MAX_CONTEXT_LENGTH = 8192; // 8K characters max (reduced from 16K)
  17.   const actualContextLength = Math.min(tryContextLength, MAX_CONTEXT_LENGTH);
  18.   const halfContextLength = Math.floor(actualContextLength / 2);
  19.  
  20.   const selection = window.getSelection();
  21.   if (!selection || selection.rangeCount === 0 || selection.toString().trim() === '') {
  22.     return { selectedText: null, textBefore: null, textAfter: null, paragraphText: null };
  23.   }
  24.  
  25.   const selectedText = selection.toString().trim();
  26.   const range = selection.getRangeAt(0);
  27.  
  28.   // Helper function to get text nodes in document order
  29.   function getTextNodesIn(node) {
  30.     const textNodes = [];
  31.     const walk = document.createTreeWalker(node, NodeFilter.SHOW_TEXT, null, false);
  32.     let currentNode;
  33.     while (currentNode = walk.nextNode()) {
  34.       textNodes.push(currentNode);
  35.     }
  36.     return textNodes;
  37.   }
  38.  
  39.   // Get all text nodes in document
  40.   const allTextNodes = getTextNodesIn(document.body);
  41.  
  42.   // Find start and end text nodes of the selection
  43.   const startNode = range.startContainer;
  44.   const endNode = range.endContainer;
  45.  
  46.   let textBefore = '';
  47.   let textAfter = '';
  48.  
  49.   // Collect text before the selection
  50.   let beforeIndex = allTextNodes.findIndex(node => node === startNode) - 1;
  51.   let currentLength = 0;
  52.  
  53.   // First add partial text from the start node itself
  54.   if (startNode.nodeType === Node.TEXT_NODE) {
  55.     textBefore = startNode.textContent.substring(0, range.startOffset) + textBefore;
  56.     currentLength = textBefore.length;
  57.   }
  58.  
  59.   // Then add text from previous nodes
  60.   while (beforeIndex >= 0 && currentLength < halfContextLength) {
  61.     const node = allTextNodes[beforeIndex];
  62.     const nodeText = node.textContent;
  63.  
  64.     // Add the entire node's text
  65.     textBefore = nodeText + '\n' + textBefore;
  66.     currentLength += nodeText.length;
  67.  
  68.     beforeIndex--;
  69.   }
  70.  
  71.   // If we didn't get enough context, add ellipsis
  72.   if (beforeIndex >= 0) {
  73.     textBefore = '...\n' + textBefore;
  74.   }
  75.  
  76.   // Collect text after the selection
  77.   let afterIndex = allTextNodes.findIndex(node => node === endNode) + 1;
  78.   currentLength = 0;
  79.  
  80.   // First add partial text from the end node itself
  81.   if (endNode.nodeType === Node.TEXT_NODE) {
  82.     textAfter += endNode.textContent.substring(range.endOffset);
  83.     currentLength = textAfter.length;
  84.   }
  85.  
  86.   // Then add text from subsequent nodes
  87.   while (afterIndex < allTextNodes.length && currentLength < halfContextLength) {
  88.     const node = allTextNodes[afterIndex];
  89.     const nodeText = node.textContent;
  90.  
  91.     // Add the entire node's text
  92.     textAfter += nodeText + '\n';
  93.     currentLength += nodeText.length;
  94.  
  95.     afterIndex++;
  96.   }
  97.  
  98.   // If we didn't get all the text, add ellipsis
  99.   if (afterIndex < allTextNodes.length) {
  100.     textAfter += '\n...';
  101.   }
  102.  
  103.   // Clean up and trim the text
  104.   textBefore = textBefore.trim();
  105.   textAfter = textAfter.trim();
  106.  
  107.   // Combine everything for paragraph text
  108.   const paragraphText = (textBefore + ' ' + selectedText + ' ' + textAfter).trim();
  109.  
  110.   return { selectedText, textBefore, textAfter, paragraphText };
  111. }
  112.  
  113. // Export the function for use in other scripts
  114. if (typeof module !== 'undefined' && module.exports) {
  115.   module.exports = { GetSelectionContext };
  116. } else {
  117.   // For direct browser use
  118.   window.SelectionUtils = window.SelectionUtils || {};
  119.   window.SelectionUtils.GetSelectionContext = GetSelectionContext;
  120. }