JavaScript 正则表达式性能。

Question

我有一个函数可以纠正异常大写单词列表的大小写：

var line = "some long string of text";
["AppleScript", "Bluetooth", "DivX", "FireWire", "GarageBand", 
 "iPhone", "iTunes", "iWeb", "iWork", "JavaScript", "jQuery", "MacBook", 
 "MySQL", "PowerBook", "PowerPoint", "QuickTime", "TextEdit", "TextMate",
 // ... 
 "Wi-Fi", "Xcode", "Xserve", "XMLHttpRequest"].forEach(function(name) {
      line = line.replace(RegExp(name, "gi"), name);
});

现在我面临的问题是大多数输入字符串平均包含 0 到 3 个这些单词。显然，现在我正在执行数十个（可能还有数百个；随着时间的推移，该数组有一种不可思议的增长趋势）函数调用，这些函数调用基本上什么都不做。

我怎样才能使这段代码更快并摆脱不必要的函数调用？

示例输入：

我的 iphone 应用程序在 UIViewController 下有一个用户表单。当我再次启动应用程序时，我的一些 UIView 会更改其位置和大小。 （这些 UIViews 取决于键盘位置）某处绝对是我的错。我试图弄清楚当应用程序从后台再次启动时发生了什么以及 UIView 更改可以在哪里完成。

Answer 1

您可以构建包含所有单词的正则表达式，通过将每个单词括在括号中来捕获它。在替换中使用它可以提供足够的信息来恢复替换函数中的原始单词。

  function correct (text, words) {
    return text.replace (RegExp ('\\b(?:(' + words.join (')|(') + '))\\b', 'ig'), function (m) {
      for (var a = arguments.length - 2; a--;)
        if (arguments[a])
      return words[a-1] || m;
    });
  } 

  console.log (correct ("My iphone itunes divx firewire application has a user form under uiviewcontroller. When I start application again some of my uiview changes its positions and sizes. (These uiviews depend on keyboard position) Somewhere is definitely my fault. I try to figure what is going on when application starts again from background and where the uiview changes can be done.",
    ["AppleScript", "Bluetooth", "DivX", "FireWire", "GarageBand", 
 "iPhone", "iTunes", "iWeb", "iWork", "JavaScript", "jQuery", "MacBook", 
 "MySQL", "PowerBook", "PowerPoint", "QuickTime", "TextEdit", "TextMate",
 // ... 
 "UIViewController","UIView",
 "Wi-Fi", "Xcode", "Xserve", "XMLHttpRequest"]));
My iPhone iTunes DivX FireWire application has a user form under UIViewController. When I start application again some of my UIView changes its positions and sizes. (These UIViews depend on keyboard position) Somewhere is definitely my fault. I try to figure what is going on when application starts again from background and where the UIView changes can be done.

This turns out to be faster then the original code.