未捕获的类型错误：对象在 XMLHttpRequest 中不可迭代（无法读取属性 Symbol(Symbol.iterator)）。<anonymous>

Question

const container = document.querySelector("#container");

request.open("GET","https://datausa.io/api/data?drilldowns=Nation&measures=Population") ; 


request.send();

// to get the response


request.addEventListener("load",function(){

    //  console.log( this.responseText);

     const [data]= JSON.parse(this.responseText);
     console.log(data);

    //  const htmlData ="<div></div>";
    // container.insertAdjacentHTML("afterbegin",htmlData)
})

我在 JSON.parse(this.responseText) 中遇到错误，上面提到的错误是针对这一行的，请帮我解决它

Answer 1

您不需要 [] 或 {} 环绕数据。 在这种情况下，只有数据就足够了。

const data = JSON.parse(this.responseText);

Answer 2

调用返回：

{"data":[{"ID Nation":"01000US","Nation":"United States","ID Year":2019,"Year":"2019","Population":328239523,"Slug Nation":"united-states"},{"ID Nation":"01000US","Nation":"United States","ID Year":2018,"Year":"2018","Population":327167439,"Slug Nation":"united-states"},{"ID Nation":"01000US","Nation":"United States","ID Year":2017,"Year":"2017","Population":325719178,"Slug Nation":"united-states"},{"ID Nation":"01000US","Nation":"United States","ID Year":2016,"Year":"2016","Population":323127515,"Slug Nation":"united-states"},{"ID Nation":"01000US","Nation":"United States","ID Year":2015,"Year":"2015","Population":321418821,"Slug Nation":"united-states"},{"ID Nation":"01000US","Nation":"United States","ID Year":2014,"Year":"2014","Population":318857056,"Slug Nation":"united-states"},{"ID Nation":"01000US","Nation":"United States","ID Year":2013,"Year":"2013","Population":316128839,"Slug Nation":"united-states"}],"source":[{"measures":["Population"],"annotations":{"source_name":"Census Bureau","source_description":"The American Community Survey (ACS) is conducted by the US Census and sent to a portion of the population every year.","dataset_name":"ACS 1-year Estimate","dataset_link":"http://www.census.gov/programs-surveys/acs/","table_id":"B01003","topic":"Diversity","subtopic":"Demographics"},"name":"acs_yg_total_population_1","substitutions":[]}]} 

正如您所看到的，这是一个对象而不是数组，因此要从对象中获取数据键，您需要使用大括号而不是普通括号。

像这样：

const {data} = JSON.parse(this.responseText);