如何在后续调用中重用casperJS调用中填充的变量？ [英] How can I reuse a variable populated within a casperJS call in a subsequent call?

问题描述

我在CasperJS脚本中遇到以下范围问题。传递给casper.thenOpenAndEvaluate（）时，baseTargetUrl是未定义的。为什么会这样，我该如何解决？

I have the following scoping problem in a CasperJS script. baseTargetUrl is undefined when passing into casper.thenOpenAndEvaluate(). Why is this and how can I work around it?

var baseTargetUrl;
        .....
casper.then(function() {
    baseTargetUrl = this.evaluate(function() {
        return __utils__.getElementByXPath('//*[@id="wrapper"]/div[1]/a[2]')["href"];
    });
    console.log('logging: '+baseTargetUrl); // works
});

casper.thenOpenAndEvaluate(baseTargetUrl ,function() { //baseTargetUrl is undefined here
    var test = document.querySelector('myselector');
    //do other stuff

});

推荐答案

如您所知，我们无法从外部获取变量异步调用。

As you know we can't grab variable from outside async calls. This seem kinda hacky but this is the best I've got for now ....

var baseTargetUrl;
        .....
casper.then(function() {
    baseTargetUrl = this.evaluate(function() {
        return __utils__.getElementByXPath('//*[@id="wrapper"]/div[1]/a[2]')["href"];
    });
    console.log('logging: '+baseTargetUrl); // works

    this.thenOpenAndEvaluate(baseTargetUrl ,function() { // 'this' being the instance of casper
        var test = document.querySelector('myselector');
        //do other stuff

    });
});

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