对象数组检查它是否包含键值对；在哪个位置-Javascript [英] Array of objects check if it includes key value pair; on which position - Javascript

问题描述

我尝试检查对象数组是否具有带有键 service_tags 的键值对和包含字符串"trace"的 array 的值.如果这个数组有它，我也想返回对象的位置.

I try to check if an array of object has a key value pair with the key service_tags and a value of an array including the string "trace". If this array has it, I also want to return the position of the object.

我的尝试返回 undefined .

gg.fields =
[  
    { ... },
    {value: "D", display_name: "Nat."},
    {  
       "value":"Likes redwine",
       "display_name":"Trace 2",
       "servicio_tags":[  
          "trace"
       ]
    }
 ]


 //function    

 let traceFieldExists = gg.fields.forEach((field, positionOfTraceField) => {
        if (field.servicio_tags && field.servicio_tags[0] === 'trace') {
            return {
              positionOfTraceField : positionOfTraceField,
              exists : true
            };
          } else {
            return {exists : false};
        }
      });

感谢您的帮助！

推荐答案

我尝试检查对象数组是否具有带有键service_tags的键值对和包含字符串"trace"的数组值

I try to check if an array of object has a key value pair with the key service_tags and a value of an array including the string "trace"

forEach 不这样做.它总是返回未定义.如果您只想是否存在此类条目，请使用 查找 .如果要第一个匹配条目的 index ，请使用

forEach doesn't do that. It always returns undefined. If you just want to know if such an entry exists, use some. If you want to retrieve the first matching entry, use find. If you want the index of the first matching entry, use findIndex.

您的编辑在标题上添加了在哪个位置"，这使我认为您想要 findIndex :

Your edit adds "on which position" to the title, which makes me think you want findIndex:

let traceFieldIndex = gg.fields.findIndex(field => {
    return field.servicio_tags && field.servicio_tags[0] === 'trace';
});

traceFieldIndex 将包含数组中回调为其返回真值的第一个条目的索引，如果处理了完整数组和回调，则为 -1 从未返回真实值.

traceFieldIndex will contain the index of the first entry in the array for which the callback returned a truthy value, or -1 if the full array was processed and the callback never returned a truthy value.

如果 field.servicio_tags 可能具有'trace'而不是索引0，则可能需要

If field.servicio_tags might have 'trace' but not at index 0, you might want includes there:

let traceFieldIndex = gg.fields.findIndex(field => {
    return field.servicio_tags && field.servicio_tags.includes('trace');
});

这将搜索 field.servicio_tags 中的所有条目，而不仅仅是查看第一个条目.

That will search all the entries in field.servicio_tags instead of just looking at the first one.

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