使用 Node.js 对文本内容分词和关键词抽取

有了HTTP/2，不使用雪碧图、压缩、拼接，也可以提升性能。然而，这不代表不应该使用这些技术。不过这已经清楚表明了我们从HTTP/1.1移动到HTTP/2的必要性。
`;

const nodejieba = require("nodejieba");
const result = nodejieba.extract(content, 20);
console.log(result);

输出的结果类似下面这样：

[ { word: 'HTTP', weight: 140.8704516850025 },
 { word: '请求', weight: 14.23018001394 },
 { word: '应该', weight: 14.052171126120001 },
 { word: '万维网', weight: 12.2912397395 },
 { word: 'TCP', weight: 11.739204307083542 },
 { word: '1.1', weight: 11.739204307083542 },
 { word: 'Web', weight: 11.739204307083542 },
 { word: '雪碧图', weight: 11.739204307083542 },
 { word: 'HTTPS', weight: 11.739204307083542 },
 { word: 'IP', weight: 11.739204307083542 },
 { word: '应用层', weight: 11.2616203224 },
 { word: '客户端', weight: 11.1926274509 },
 { word: '浏览器', weight: 10.8561552143 },
 { word: '拼接', weight: 9.85762638414 },
 { word: '比较', weight: 9.5435285574 },
 { word: '网页', weight: 9.53122979951 },
 { word: '服务器', weight: 9.41204128224 },
 { word: '使用', weight: 9.03259988558 },
 { word: '必要性', weight: 8.81927328699 },
 { word: '添加', weight: 8.0484751722 } ]

我们添加一些新的关键词到字典里：

性能
HTTP/2

输出结果如下：

[ { word: 'HTTP', weight: 105.65283876375187 },
 { word: 'HTTP/2', weight: 58.69602153541771 },
 { word: '请求', weight: 14.23018001394 },
 { word: '应该', weight: 14.052171126120001 },
 { word: '性能', weight: 12.61259281884 },
 { word: '万维网', weight: 12.2912397395 },
 { word: 'IP', weight: 11.739204307083542 },
 { word: 'HTTPS', weight: 11.739204307083542 },
 { word: '1.1', weight: 11.739204307083542 },
 { word: 'TCP', weight: 11.739204307083542 },
 { word: 'Web', weight: 11.739204307083542 },
 { word: '雪碧图', weight: 11.739204307083542 },
 { word: '应用层', weight: 11.2616203224 },
 { word: '客户端', weight: 11.1926274509 },
 { word: '浏览器', weight: 10.8561552143 },
 { word: '拼接', weight: 9.85762638414 },
 { word: '比较', weight: 9.5435285574 },
 { word: '网页', weight: 9.53122979951 },
 { word: '服务器', weight: 9.41204128224 },
 { word: '使用', weight: 9.03259988558 } ]

在这个基础上，我们采用白名单的方式过滤出一些可以作为 tag 的词：

const content = `

HTTP、HTTP/2与性能优化

本文的目的是通过比较告诉大家，为什么应该从HTTP迁移到HTTPS，以及为什么应该添加到HTTP/2的支持。在比较HTTP和HTTP/2之前，先看看什么是HTTP。