如何在 Javascript 中访问包含空值的 JSON 字符串

Question

我有这个 JSON 我从包含空值的 API 中检索。如何更好地遍历 JSON 并抽象功能？

const colletionjson = 
      { "collections": 
        [ { "title"          : "Home page"
          , "description"    : null
          , "image"          : null
          } 
        , { "title"          : "Products"
          , "description"    : "Products"
          , "image"          : { "src": "https:www.example.com" } 
          , "products_count" : 3
          } 
        ] 
      } 

$.each(collectionjson, function (key, value) {
  $.each(value, function (key, value) {

    var collectionTitle = value.title;
    var collectionDescription = value.description;

    if (value == "image" && $.isArray(value)) {
      var collectionImage = value.image.src;
    } else {
      var collectionImage = "";
    }
  });
});
  // Do something with the data

Answer 1

if (colletionjson.collections && Array.isArray(colletionjson.collections)) {
  colletionjson.collections.forEach(value => {
    const collectionTitle = value.title;
    const collectionDescription = value.description;
    let collectionImage = '';
    if (value.image && value.image.src) {
      collectionImage = value.image.src;
      // do something with this value
    } 
  })
}

Answer 2

您现在可以使用 Optional chaining (?.) ECMAScript 2020

示例代码

const colletionjson =   // just a name
      { collections: 
        [ { title          : 'Home page'
          , description    : null
          , image          : null
          } 
        , { title          : 'Products'
          , description    : 'Products'
          , image          : { src : 'https:www.example.com' } 
          , products_count : 3
          } 
        ] 
      } 

colletionjson.collections.forEach((collection, i) =>
  {
  let collectionTitle       = collection.title
    , collectionDescription = collection.description  || ''
    , collectionImage       = collection.image?.src || '' 
    ;
  console.log (`index: ${i}, title: ${collectionTitle}, description: ${collectionDescription}, image: ${collectionImage}` )
  })

如何在 Javascript 中访问包含空值的 JSON 字符串

How to access JSON string containing null value in Javascript

javascript

jquery

json

shopify

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