CasperJS找不到jQuery [重复]

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• Pass a JavaScript function as parameter 13 answers

传递JavaScript函数作为参数13答案

I'm using jQuery selectors for casper.js scraping. I understand that it's necessary to place the jQuery calls inside casper.evaluate().

我正在使用jQuery选择器进行casper.js抓取。我知道有必要将jQuery调用放在casper.evaluate()中。

The problem is that in the last of these following three functions, a ReferenceError: Can't find variable: $ is raised. The first two work absolutely fine.

问题是,在以下三个函数的最后一个中,一个ReferenceError:找不到变量:$被引发。前两个工作绝对没问题。

// On main page, scrape links to sub-pages.
function getLinks() {
    var links = $('li.ds-artifact-item a');
    return Array.prototype.map.call(links, function(e) {
        return e.getAttribute('href');
    });
}

// On main page, scrape sub-pages' titles.
function getTitles() {
    var titles = $('li.ds-artifact-item a');
    return Array.prototype.map.call(titles, function(e) {
        return e.innerHTML;
    });
}

// On sub-page, scrape document description.
function getDescription(){
    var descriptions = $('td.label-cell:contains(date)');
    return Array.prototype.map.call(descriptions, function(e) {
        return e.innerHTML;
    });
}

Here's the rest of the script, with the unimportant details obscured. Note that anotherValidPage is a valid URL which returns HTTP 200 (success).

这是脚本的其余部分,不重要的细节模糊不清。请注意,anotherValidPage是一个返回HTTP 200(成功)的有效URL。

var links = []; var titles = []; var descriptions = [];

casper.start(validPage, function() {
    links = this.evaluate(getLinks);
    titles = this.evaluate(getTitles);
});


casper.then(function() {
    // echo results
    this.echo(links.length + ' links found:');
    this.echo(' - ' + links.join('\n - '));
    this.echo(titles.length + ' titles found:');
    this.echo(' - ' + titles.join('\n - '));
    });

casper.thenOpen(anotherValidPage, function(){});

casper.then(function(){
    // This call is the problematic one.
    descriptions = this.evaluate(getDescription());

    this.echo(descriptions.length + ' descriptions found:');
    this.echo(' - ' + descriptions.join('\n - '));
});

casper.run();

1 个解决方案

#1

I found the solution: instead of calling this.evaluate(getDescription()) I had to call this.evaluate(getDescription), since I guess I was executing the function instead of passing it as an argument, whoops.

我找到了解决方案:而不是调用this.evaluate(getDescription())我不得不调用this.evaluate(getDescription),因为我想我正在执行函数而不是将其作为参数传递,哎呀。