javascript - 如何从 JSON 对象中提取多个主题标签？

Question

我正在尝试从下面的 JSON 对象中提取“动物”和“鱼”主题标签。我知道如何提取名为“动物”的第一个实例，但我不知道如何提取这两个实例。我正在考虑使用循环，但不确定从哪里开始。请指教。

data = '{"hashtags":[{"text":"animal","indices":[5110,1521]},
        {"text":"Fish","indices":[122,142]}],"symbols":[],"user_mentions":
        [{"screen_name":"test241","name":"Test 
        Dude","id":4999095,"id_str":"489996095","indices":[30,1111]},
        {"screen_name":"test","name":"test","id":11999991,
        "id_str":"1999990", "indices":[11,11]}],"urls":[]}'; 

function showHashtag(data){
   i = 0;
   obj = JSON.parse(data); 
   console.log(obj.hashtags[i].text);
}

showHashtag(data);

Answer 1

使用Array.prototype.filter() :

let data = '{"hashtags":[{"text":"animal","indices":[5110,1521]},{"text":"Fish","indices":[122,142]}],"symbols":[],"user_mentions":[{"screen_name":"test241","name":"Test Dude","id":4999095,"id_str":"489996095","indices":[30,1111]},   {"screen_name":"test","name":"test","id":11999991,        "id_str":"1999990", "indices":[11,11]}],"urls":[]}';

function showHashtag(data){
    return JSON.parse(data).hashtags.filter(e => /animal|fish/i.test(e.text))
}

console.log(showHashtag(data));

为了使该函数可重用，如果您想查找其他“主题标签”，您可以像这样传递一个数组:

function showHashtag(data, tags){
    let r = new RegExp(tags.join("|"), "i");
    return JSON.parse(data).hashtags.filter(e => r.test(e.text))
}

console.log(showHashtag(data, ['animal', 'fish']));

要仅获取文本属性，只需链接 map()

console.log(showHashtag(data, ['animal', 'fish']).map(e => e.text));

或者在函数中

return JSON.parse(data).hashtags
    .filter(e => /animal|fish/i.test(e.text))
    .map(e => e.text);

编辑:

如果您只需要一个包含 ['animal', 'fish'] 的数组，我真的不明白为什么要按动物和鱼类进行过滤。要仅获取具有文本属性的对象，请再次使用过滤器，但像这样

let data = '{"hashtags":[{"text":"animal","indices":[5110,1521]},{"text":"Fish","indices":[122,142]}],"symbols":[],"user_mentions":[{"screen_name":"test241","name":"Test Dude","id":4999095,"id_str":"489996095","indices":[30,1111]},   {"screen_name":"test","name":"test","id":11999991,        "id_str":"1999990", "indices":[11,11]}],"urls":[]}';

function showHashtag(data){
    return JSON.parse(data).hashtags
      .filter(e => e.text)
      .map(e => e.text);
}

console.log(showHashtag(data));