Is there any way to use a dynamic key with node-mongodb-native?

Is there any way to use dynamic keys with the node-mongodb-native driver? By this I mean having a variable hold the key instead of using the key directly.

As in when one would normally do this:

db.createCollection('col', function(err, col){

to do this instead:

db.createCollection('col', function(err, col){
    var ID = '_id';

When I run the latter code, I end up with a document in collection db.col with a key called ID in addition to a standardly created _id, as opposed to just a key _id with the value wak3ajakar00. This leads me to believe that it isn't actually possible to do this directly.

Instead, I'm now just creating the document that I want to insert ahead of time as follows:

db.createCollection('col', function(err, col){
    var ID = 'wak3ajakar00';
    var key = '_id';
    insertion = {}
    insertion[key] = ID;

This works exactly like I want it to, but I just wanted to know if there are any better ways to go about this. JavaScript, NodeJS, and MongoDB are all new to me, so I feel like I could easily be missing something. If not, are there any cleaner ways to write the above code in JavaScript?

Best, and thanks,



In object literal syntax, you cannot use a variable as the key name, only values. The way to do it, is the way you already discovered - create your object first, then add the property as a separate step using square bracket notation.

var obj = {};
var ID = "_id";
obj[ID] = "wak3ajakar00";

You can write a small function that creates such an object

var obj = function(key, value, obj) {
  obj = obj || {};
  obj[key] = value;
  return obj;

// Usage
foo = obj('foo' + 'bar', 'baz');
// -> {'foobar': 'baz'}

foo = obj('stack' + 'over', 'flow', foo);
// -> {'foobar': 'baz', 'stackover': 'flow'}

Don't know if calling this function obj is a good idea.


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