Question

我很难将this传递给我的函数，如下所示：

console.log('geolocation is ' + this.isGeolocating);

let geocoder = new google.maps.Geocoder;
geocoder.geocode({'location': geolocation}, function(results, status, self = this) {
    console.log('geolocation is ' + self.isGeolocating);
    if (status === 'OK') {
        if (results[0]) {
            console.log(results[0]);
            self.geolocated = 'success';
        } else {
            // No results found
            self.geolocated = 'error';
        }
    } else {
        console.log('Geocoder failed due to: ' + status);
        self.geolocated = 'error';
    }
});

this.isGeolocating = false;

在函数之前和之后可以正确访问

this，但是如何通过它？在我的情况下，self也是未定义的。

Answer 1

通常有三种方法。一种方法是在函数之前将self分配给另一个变量，通常命名为that或let that = this; geocoder.geocode(..., function(...) { that.isGeolocating });;变量将被捕获到函数的closure。

this

另一种方法是使用bind明确告诉函数geocoder.geocode(..., function(...) { this.isGeolocating }.bind(this));应该是什么：

this

第三个是使用rocket function，但不会重新分配geocoder.geocode(..., (...) => { this.isGeolocating });：

this

Answer 2

试试这个：

let myBeautifulThis = this;
let geocoder = new google.maps.Geocoder;
geocoder.geocode({'location': geolocation}, function(results, status) {
  console.log('geolocation is ' + myBeautifulThis.isGeolocating);
});

Answer 3

您需要在函数外部的变量中存储对let self = this; geocoder.geocode({'location': geolocation}, function(results, status) { // you existing code here // use self.isGeolocating });的引用，或使用箭头函数。

所以要么

geocoder.geocode({'location': geolocation}, (results, status) => {
    // using this in here will use the this of the outer scope.
    // use this.isGeolocating
});

只是

from selenium import webdriver

driver = webdriver.Chrome("E:\Tutorial\Driver\chromedriver.exe")

words = ['girl', 'cat', 'dog', 'bird', 'man']
for word in words:
    driver.get("https://translate.google.com.eg/?hl=en&tab=wT#en/fr/" + word)

translations = driver.find_elements_by_class_name('gt-baf-word-clickable')

for text in translations:
    print(text.text)

如何正确传递＆＃34;这个＆＃34;进入功能？

3 个答案: