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javascriptjsonstringify

Hide null values in output from JSON.stringify()


In my code, all of the info from a Postgres table row are stringified when a specific rowID is selected.

var jsonRes = result.message.rows;

document.getElementById('panel').innerHTML = '<pre>' + JSON.stringify(jsonRes[0], null, "\t") + '</pre>'

The result looks something like this:

{
  "ogc_fid": 143667,
  "relkey": 288007,
  "acct": "000487000A0010000",
  "recacs": "12.5495 AC",
  "shape_star": 547131.567383,
  "shape_stle": 3518.469618,
  "objectid": 307755,
  "zone_dist": "MU-3",
  "pd_num": null,
  "council_da": null,
  "long_zone_": "MU-3",
  "globalid": "{D5B006E8-716A-421F-A78A-2D71ED1DC118}",
  "ord_num": null,
  "notes": null,
  "res_num": null,
  "effectived": 1345766400000,
  "shape.star": 629707.919922,
  "shape.stle": 3917.657332,
  "case_numbe": null,
  "common_nam": null,
  "districtus": null 
}

I am new to JS and would like to know if there might be a simple way to completely exclude the columns containing null values - a function that roughly looks like this:

function hide(jsonObject) {
    if (property === null) {
      hide property
  } else {
      return str
  }
}

So that in the end, the object in the panel looks like this:

{
  "ogc_fid": 143667,
  "relkey": 288007,
  "acct": "000487000A0010000",
  "recacs": "12.5495 AC",
  "shape_star": 547131.567383,
  "shape_stle": 3518.469618,
  "objectid": 307755,
  "zone_dist": "MU-3",
  "long_zone_": "MU-3",
  "globalid": "{D5B006E8-716A-421F-A78A-2D71ED1DC118}",
  "effectived": 1345766400000,
  "shape.star": 629707.919922,
  "shape.stle": 3917.657332
}

Solution

  • Thanks for the replies. I just realized that JSON.stringify() has a REPLACER parameter (info here)

    So I just added:

    function replacer(key, value) {
      // Filtering out properties
      if (value === null) {
        return undefined;
      }
      return value;
    }
    
    document.getElementById('panel').innerHTML =
      '<pre>' +
        JSON.stringify(jsonRes[0], replacer, "\t") +
      '</pre>'
    ;