通过键截取值的迭代函数

Question

我有一个大的 JSON 文件，我想截取所有与它们关联的键 text 的值，例如：

    type":"doc",
   "content":[
      {
         "type":"paragraph",
         "content":[
            {
               "text":"this is a simple page, about a simple umbrella.",
               "type":"text"
            }
         ]
      },
      {
         "type":"paragraph",
         "content":[
            {
               "text":"you can use this text to find the umbrella page.",
               "type":"text"
            }
         ]
      },
      {
         "type":"paragraph",
         "content":[
            {
               "text":"do you like it?",
               "type":"text"
            }
         ]
      },

我知道我可以使用Object.keys，但这仅涵盖“顶级”，并没有深入。

我不想为此使用递归，而是使用迭代函数。

我尝试使用JSON.stringify，但性能不佳：

const obj = JSON.parse(content);
let ret = '';
JSON.stringify(obj, (_, nested) => {
  if (nested && nested[key]) {
    ret += nested[key] + '\n';
  }
  return nested;
});

Answer 1

如果您的目标只是获取关键文本，您可以使用以下方法。

var reg = /(?<=\")\w+(?=\"\:)/g
var jsonValue = '{"glossary": {"title": "example glossary","GlossDiv": {"title": "S","GlossList": {"GlossEntry": {"ID": "SGML","SortAs": "SGML","GlossTerm": "Standard Generalized Markup Language","Acronym": "SGML","Abbrev": "ISO 8879:1986","GlossDef": {"para": "A meta-markup language, used to create markup languages such as DocBook.","GlossSeeAlso": ["GML", "XML"]},"GlossSee": "markup"}}}}}';

console.log(jsonValue.match(reg));

Answer 2

我不确定我是否明白了这个问题，但这里是 lodash 解决方案：

const _ = require('lodash');

const data = '{"type":"doc","content":[{"type":"paragraph","content":[{"text":"this is a simple page, about a simple umbrella.","type":"text"}]},{"type":"paragraph","content":[{"text":"you can use this text to find the umbrella page.","type":"text"}]},{"type":"paragraph","content":[{"text":"do you like it?","type":"text"}]}]}';

const obj = JSON.parse(data);

const getText = (obj) => {
  const result = Object.entries(obj).reduce((acc, [key, value]) => {
    if (key === 'text') acc.push(value);
    if (_.isObject(value)) acc.push(...getText(value));
    if (_.isArray(value)) value.map((item) => getText(item));
    return acc;
  }, []);

  return result;
}

console.log(getText(obj));
// [
//   'this is a simple page, about a simple umbrella.',
//   'you can use this text to find the umbrella page.',
//   'do you like it?'
// ]