Check for null & replace it with empty string for all properties in a object using jQuery and JavaScript

问题

I have a JSON object, which includes other objects and list of objects. Have to write a function, which iterates through all properties of objects as well as object within object and list of objects and replace null with an empty string.

As it is loop inside loop, I need to implement deferred so sequential processing. I tried many ways, but failed. Anyone please help.

function ValidateObject(result) {
  var aObj = result.A;
  aObj = VerifyForNull(aoBJ);
  var bObj = result.B;
  bObj = VerifyForNull(bObJ);
  for (var i = 0; i < result.C.length; i++) {
    var cObj = result.C[i];
    cObj = VerifyForNull(cObJ);
    for (var j = 0; j < cObj.D.length; j++) {
      var dObj = cObj.D[i];
      dObj = VerifyForNull(dObj);
    }
  }
}

function VerifyForNull(obj) {
  Object.keys(obj).forEach(function(key) {
    var val = obj[key];
    if (val == null || value === undefined) {
      obj[key] = "";
    }
  });
}

回答1:

You can use JSON.Stringify (see MDN) with a replacer method to replace all nulls in an Object:

console.log(replaceNull({
    x: {},
    y: null,
    z: [1,null,3,4],
    foo: "foo",
    bar: {foobar: null}
  }));

const yourObj = { "person": { "id": 12345, "name": "John Doe", "phones": { "home": "800-123-4567", "mobile": null }, "email": [ "jd@example.com", "jd@example.org" ], "dateOfBirth": null, "registered": true, "emergencyContacts": [ { "name": "Jane Doe", "phone": null, "relationship": "spouse" }, { "name": "Justin Doe", "phone": "877-123-1212", "relationship": undefined } ] } };

console.log(replaceNull(yourObj, ""));

function replaceNull(someObj, replaceValue = "***") {
  const replacer = (key, value) => 
    String(value) === "null" || String(value) === "undefined" ? replaceValue : value;
  //^ because you seem to want to replace (strings) "null" or "undefined" too
  
  return JSON.parse( JSON.stringify(someObj, replacer));
}

回答2:

UPDATE: Since your example objects have keys with value "null" which are Strings and not Objects with value null i updated my answer to correspond your needs.

Try to solve the problem recursive. Everytime the algorithm finds an object in the object the validation routine is called upon this 'new' object.

Here is my fiddle which illustrates a solution: https://jsfiddle.net/vupry9qh/13/

function isNull(obj, key) {
    return (obj[key] == null || obj[key] === undefined || obj[key] === "null");
}

function validate(obj) {
    var objKeys = Object.keys(obj);
  objKeys.forEach((key) => {
    if(isNull(obj, key)) {
        obj[key] = "";
    }
    if(typeof(obj[key]) == "object") {
        validate(obj[key]);
    }
  });
}

来源：https://stackoverflow.com/questions/51513158/check-for-null-replace-it-with-empty-string-for-all-properties-in-a-object-usi

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javascript

jquery

promise

deferred