javascript - 这个多行 url 字符串有什么问题？

Question

我正在尝试使用 ES6 模板文字来表示多行字符串。下面这个效果很好:

var customer = { name: "Foo" }
var card = { amount: 7, product: "Bar", unitprice: 42 }
var message = `Hello ${customer.name},
want to buy ${card.amount} ${card.product} for
a total of ${card.amount * card.unitprice} bucks?`

然后我尝试将其应用到 URL 字符串，如下所示:

let topic = "pizza";
let url = `https://en.wikipedia.org/w/api.php?action=parse&section=0&prop=text&format=json&page=${topic}`;

单行版本效果很好。但是当我将其更改为多行时，它不起作用:

let topic = "pizza";
let url = `https://en.wikipedia.org/w/api.php
?action=parse&section=0&prop=text&format=json&page=${topic}`;

or  
let url = `https://en.wikipedia.org/w/api.php\
?action=parse&section=0&prop=text&format=json&page=${topic}`;

我使用此 URL 来检索数据:

let https = require("https");
https.get(url, res => {...});

谁能告诉我多行 URL 有什么问题吗？我怎样才能正确地做呢？非常感谢。

Answer 1

您的网址中包含换行符。如果 `` 旁边有换行符，则模板文字语法允许您向字符串添加换行符，因此您的 URL 中也有换行符。

console.log('\n' === `
`) // true

在进行 HTTP 调用之前对 url 执行 String.prototype.replace()

let topic = "pizza";
let url = `https://en.wikipedia.org/w/api.php
?action=parse&section=0&prop=text&format=json&page=${topic}`;

// removes newline characters from template string
url.replace('\n', ''); 

// do your stuff here
let https = require("https");
https.get(url, res => {...});

或者转义模板字符串中的换行符

let topic = "pizza";
// escape the newline character
let url = `https://en.wikipedia.org/w/api.php\
?action=parse&section=0&prop=text&format=json&page=${topic}`;

// do your stuff here
let https = require("https");
https.get(url, res => {...});