javascript - 在 Nightwatch 自定义命令中赋值后，变量返回未定义

Question

写一个custom command进行夜间值类测试。

为什么我无法在以下代码片段中设置newValidFromText的值？

exports.command = function () {

var newValidFromText; //Want to set value to this variable

var browser= this;
browser
    .useCss()
    .perform(function() {

        //Setting the value to the variable 'newValidFromText'
        newValidFromText = "June 1, 2017 "

        //Testing the value set - console prints "June 1, 2017"
        console.log( "newValidFromText now is: "+ newValidFromText );
    })

    .waitForElementVisible('input[id*="SubscriptionStart"]')

    //Test for correct value - getting validFromText = undefined
    .verify.valueContains('input[id*="SubscriptionStart"]', validFromText) 
 return browser.useCss();
};

Answer 1

因为您要求变量超出可见区域

exports.command = function () {

var newValidFromText; //Want to set value to this variable

var browser= this;
 browser
.useCss()
.perform(function() {

    //Setting the value to the variable 'newValidFromText'
    newValidFromText = "June 1, 2017 "

    //Testing the value set - console prints "June 1, 2017"
    console.log( "newValidFromText now is: "+ newValidFromText );

this.waitForElementVisible('input[id*="SubscriptionStart"]') 

    .verify.valueContains('input[id*="SubscriptionStart"]', validFromText); 

})

};