如何使用下划线从对象内的数组中删除空，空，未定义的值

Question

我想删除与null关联的所有键，我尝试了_.filter，_。compact，_。reject，但对我来说却无用，正在使用最新版本的下划线1.8.3。

这是我尝试的：

_.reject(Obj,function (value) {
    return value===null;
})

_.compact(Obj)

宾语：

    var Obj =  {
  "pCon": [
    {
      "abc": null,
      "def": null,
      "ghi": {
        "content": "abc"
      }
    },
    {
      "abc": null,
      "def": {
        imgURL: "test.png"
      },
      "ghi": null
    },
    {
      "abc": {
        "key": "001"
      },
      "def": null,
      "ghi": null
    }
  ]
}

Answer 1

递归样式的纯Java解决方案。

 function deleteNull(o) { if (typeof o === 'object') { Object.keys(o).forEach(function (k) { if (o[k] === null) { // or undefined or '' ...? delete o[k]; return; } deleteNull(o[k]); }); } } var object = { "pCon": [{ "abc": null, "def": null, "ghi": { "content": "abc" } }, { "abc": null, "def": { imgURL: "test.png" }, "ghi": null }, { "abc": { "key": "001" }, "def": null, "ghi": null }] }; deleteNull(object); document.write('<pre>' + JSON.stringify(object, 0, 4) + '</pre>'); 

Answer 2

 for (var i in Obj["pCon"]) {
  if (Obj["pCon"][i]["abc"] === null || Obj["pCon"][i]["abc"] === undefined) {
  // test[i] === undefined is probably not very useful here
    delete Obj["pCon"][i]["abc"];
  }
  if (Obj["pCon"][i]["def"] === null || Obj["pCon"][i]["def"] === undefined) {
  // test[i] === undefined is probably not very useful here
    delete Obj["pCon"][i]["def"];
  }
  if (Obj["pCon"][i]["ghi"] === null || Obj["pCon"][i]["ghi"] === undefined) {
  // test[i] === undefined is probably not very useful here
    delete Obj["pCon"][i]["ghi"];
  }
}

它在jsfiddle中工作https://jsfiddle.net/3wd7dmex/1/

Answer 3

这是使用下划线的解决方案。 请注意，这不会像Nina的解决方案那样递归地深入结构。 但是，如果需要，您可以扩展它以反映该行为。

 var obj = { "pCon": [{ "abc": null, "def": null, "ghi": { "content": "abc" } }, { "abc": null, "def": { imgURL: "test.png" }, "ghi": null }, { "abc": { "key": "001" }, "def": null, "ghi": null }] }; var result = _.chain(obj).map(function(value, key) { value = _.map(value, function(singleObj) { return _.pick(singleObj, _.identity) // pick the keys where values are non empty }); return [key, value]; }).object().value(); document.write('<pre>' + JSON.stringify(result, 0, 4) + '</pre>'); 

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