Object with Array remove element behaviour

Question

Here the question, I have an Object contain several elements in it

Example:

obj = { "0": { "a": "a1", "b": "b1"}, "1": { "a": "a2", "b": "b2"} };

And now, i wish to remove/delete the element 0, so it will be only element 1 left, but instead of the expected result of deleting element from an Object, i would like it act like an Array, the second element will replace the first element, with the example above, 1 will rename into 0 as well as all the element following onward.

Note: It may contain more than 2 element in the object, and is not necessary will remove the first element, it could be any element within the object

Here the solution i done so far,

var index = 0 //just for demo purpose var tempArr = Object.keys(obj).map(function(key){ return obj[key]; }); tempArr.splice(index,1); obj = tempArr.reduce(function(acc, cur, i){ acc[i] = cur; return acc; }, {});

result:

obj = { "0": { "a": "a2", "b": "b2"} }

This solution works and gave the result I want, but is there any better to do this?

Edited: As conclusion of the suggestion and discussion

Alternative way to solve the problem, which giving the almost identical result as my solution.

function Delete(index) { delete obj[index]; var keys = Object.keys(obj); var update = false; for (var i = index + 1; i <= keys.length; i++) { obj[i - 1] = obj[i]; update = true; } if (update) delete obj[keys[keys.length - 1]]; }

by @Anthony McGrath

delete obj[index]; obj = Object.keys(obj).reduce(function(newobj,key,i){ newobj[i]=obj[key]; return newobj; },{});

by @Alexandru-Ionut Mihai

obj.length = Math.max.apply(null, Object.keys(obj))+1; Array.prototype.splice.call(obj, index, 1); delete obj.length; // optionally delete the length again

by @t.niese

Appreciated the helps once again.

@TavishAggarwal yes. It would be the answer if the object only have 2 element, if the object having more element, it only can be use that matter within looping, which I'm trying to avoid. — Dean
– Dean, Commented Oct 13, 2017 at 6:13
@Alexandru-IonutMihai yup, it work great, compiling the conclusion, will credit you after i done. — Dean
– Dean, Commented Oct 13, 2017 at 6:41

t.niese · Accepted Answer · 2017-10-13 06:08:04Z

One thing you could do - if it has only numberic keys - is to convert it to an array like object by adding a length and then call splice on it.

obj = { "0": { "a": "a1", "b": "b1"}, "1": { "a": "a2", "b": "b2"}, "2": { "a": "a3", "b": "b3"}, "3": { "a": "a4", "b": "b4"} }; var index = 1; obj.length = Math.max.apply(null, Object.keys(obj))+1; Array.prototype.splice.call(obj, index, 1); delete obj.length; // optionally delete the length again console.dir(obj)

Mihai Alexandru-Ionut · Accepted Answer · 2017-10-13 06:09:22Z

You can do it with only reduce method.

Also, use delete operator in order to delete one property from object

obj = { "0": { "a": "a1", "b": "b1"}, "1": { "a": "a2", "b": "b2"} }; delete obj['0']; newobj=Object.keys(obj).reduce(function(newobj,key,i){ newobj[i]=obj[key]; return newobj; },{}); console.log(newobj);

Anthony McGrath · Accepted Answer · 2017-10-13 06:38:36Z

How about this?

 obj = { "0": { "a": "a1", "b": "b1"}, "1": { "a": "a2", "b": "b2"} }; function Delete(p) { delete obj[p]; var keys = Object.keys(obj); var update = false; for (var i = p + 1; i <= keys.length; i++) { obj[keys[i] - 1] = obj[keys[i]]; update = true; } if (update) delete obj[keys[keys.length - 1]]; } Delete(0); // delete first element

Nina Scholz · Accepted Answer · 2017-10-13 07:08:22Z

You could take all indices, which have to move and give it a new index/key. At the end delete the unwanted last object.

function deleteFromObject(object, index) { Object.keys(object).slice(index + 1).forEach(function (k) { object[index++] = object[k]; }); delete object[index]; } var object = { 0: { a: "a1", b: "b1" }, 1: { a: "a2", b: "b2" }, 2: { a: "a3", b: "b3" }, 3: { a: "a4", b: "b4" } }; deleteFromObject(object, 0); console.log(object); deleteFromObject(object, 2); console.log(object);

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