How to remove item from an array on condition using JavaScript

Question

I have an an array which is mentioned below. I would like to remove an item from the array which has empty property value using JavaScript.

Actual array:

[
    {
        "href":"/client",
        "methods":[]
    },
    {
        "href":"/home",
        "methods":
            {
                "type1":"GET",
                "type2":"POST",
            }
    },
    {
        "href":"/about",
        "methods":[]
    },
    {
        "href":"/contact",
        "methods":
            {
                "type1":"GET",
                "type2":"POST",
            }
    }
]

Expecting result:

[
    {
        "href":"/home",
        "methods":
            {
                "type1":"GET",
                "type2":"POST",
            }
    },
    {
        "href":"/contact",
        "methods":
            {
                "type1":"GET",
                "type2":"POST",
            }
    }
]

So, remove it when methods is an empty array?

Patrick Roberts
– Patrick Roberts

2017-11-15 04:41:16 +00:00
Commented Nov 15, 2017 at 4:41 — Patrick Roberts
– Patrick Roberts, Commented Nov 15, 2017 at 4:41
That is an array of objects, not an object.

Useless Code
– Useless Code

2017-11-15 05:51:12 +00:00
Commented Nov 15, 2017 at 5:51 — Useless Code
– Useless Code, Commented Nov 15, 2017 at 5:51

John Hooper · Accepted Answer · 2017-11-15 04:50:23Z

2

This is the job for filter. however filter does not modify the existing array so you need to assign it to a different array/overwrite the current variable

a = a.filter(item => Object.keys(item.methods).length > 0)

answered Nov 15, 2017 at 4:50

John Hooper

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2 Comments

stack shalini Over a year ago

The above syntax does not work in IE due to arrow function. Can u help me to resolve this issue in IE..

John Hooper Over a year ago

If you click on the filter link above you'll see a pretty straight forward example on how this can be used with traditional function calls. You just need to replace the arrow function with traditional function syntax. function(item){ return Object.keys(item.methods).length > 0; }

Prasun · Accepted Answer · 2017-11-15 04:48:16Z

1

Iterate over the object array and filter based on methods property length.

var obj = [...];
obj = obj.filter((val) => val.methods && val.methods.length !== 0);

answered Nov 15, 2017 at 4:48

Prasun

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Comments

Fallenreaper · Accepted Answer · 2017-11-15 04:52:05Z

In the case of methods, you can easily walk the object and then call delete on the keys with values that are empty.... or empty arrays. I expanded the answer to cover not only keys of methods where an array is empty, but all keys with what i would define as empty contents.

var l = [];
for (var i = 0; i < l.length; i++){
  var keys = Object.keys(l[i]);
  for ( var j = 0; j < keys.length; j++){
    var value = keys[j];
    // In your use case, you are only doing arrays so i coded it as such.
    if (value.length == 0){
      delete l[i][j];
    }
  }
}

If you want to expand it to cover a variety of cases such as empty string, empty arrays, empty maps, or null values you can defined a function to do that.

function isValueDeletable(value){
  if (value == null) return true;
  if (value == "") return true;
  if (value instanceof Array && value.length == 0) return true;
  if (value instanceof Map && Object.keys(value).length == 0) return true;
  return false;
}

and apply that instead of the value.length == 0;

if (isValueDeletable(value)){ delete l[i][j]; }

Then l is modified to remove all keys with empty values.

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