javascript - 使用markjs统计某个类的正则表达式匹配数

Question

我正在使用mark.js作为正则表达式辅助来突出显示字符串中的匹配项。

例如:

//negative assertions
instance.markRegExp(/not significant/g, {className: "negative"});
instance.markRegExp(/not associated/g, {className: "negative"});
instance.markRegExp(/no association/g, {className: "negative"});
//positive assertions
instance.markRegExp(/is associated/g, {className: "positive"});
instance.markRegExp(/are associated/g, {className: "positive"});
instance.markRegExp(/was associated/g, {className: "positive"});

我希望能够计算匹配类别发生的次数。

documentation显示回调功能，但我不确定是否可以将其用于此目的

var options = {
"filter": function(node, term, totalCounter, counter){
    if(term === "the" && counter >= 10){
        return false;
    } else {
        return true;
    }
}
};

Answer 1

这有点简单。您可以使用 each 或 done 回调，两者都提供计数器。使用 done 回调，您不需要自己计算，您会收到所有标记的数量，因此对您来说更容易。此外，done 回调的性能更好，因为不需要在每个标记上调用该函数。

代码如下:

var instance = new Mark(".context"),
  negativeCounter = 0,
  positiveCounter = 0;

//negative assertions
instance.markRegExp(/not significant/g, {
  className: "negative",
  done: function(counter) {
    negativeCounter += counter;
  }
});
instance.markRegExp(/not associated/g, {
  className: "negative",
  done: function(counter) {
    negativeCounter += counter;
  }
});
instance.markRegExp(/no association/g, {
  className: "negative",
  done: function(counter) {
    negativeCounter += counter;
  }
});
//positive assertions
instance.markRegExp(/is associated/g, {
  className: "positive",
  done: function(counter) {
    positiveCounter += counter;
  }
});
instance.markRegExp(/are associated/g, {
  className: "positive",
  done: function(counter) {
    positiveCounter += counter;
  }
});
instance.markRegExp(/was associated/g, {
  className: "positive",
  done: function(counter) {
    positiveCounter += counter;
  }
});

document.write("Positive counter: " + positiveCounter + ", Negative counter: " + negativeCounter);

<script src="https://cdn.jsdelivr.net/mark.js/8.8.3/mark.min.js"></script>
<div class="context">
  not significant not significant not associated no association is associated are associated was associated
</div>

以下是一些注意事项:

1. mark.js 异步工作。理论上，您应该将 .mark() 调用嵌套在 done 回调中。但是，由于您尚未启用 iframes 选项，因此它可以工作。但这样做更安全
2. 为了减少 .mark() 调用量并使代码更简单，您应该为负匹配创建一个正则表达式，为正匹配创建一个正则表达式，例如使用正则表达式组。