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Convert all key names of an object to strings

I have an object like:
obj = {"a": 1, "b": 2, c: 3}
this object is returned by a Node.js package.
I want to pass this object to a request headers but it fails because c in that object has invalid key name I guess.
Is it possible to convert all the key names of my object to strings?

You can use JSON.stringify() to convert it to a valid JSON string:
obj = JSON.stringify({"a": 1, "b": 2, c: 3});
console.log(obj)

You can create a new object and call toString() while creating the key
const obj = {
"a": 1,
"b": 2,
c: 3
};
const newObj = {};
for (let keys in obj) {
newObj[keys.toString()]: obj[keys]
}

In JavaScript, all object keys that are not symbols are converted to strings.
obj = {1: 1}
obj['1'] = 2;
// obj is {1: 2}
If you got such an 'object' from node package it means the data has not been prepared correctly - probably somebody has created JSON by hand (writing a string instead of stringify an object).
If you want to add " to all keys and change an object to a string, so, in other words, make a JSON out of it - you can use JSON.stringify(obj) //"{"a":1,"b":2,"c":3}"
If you want to make an object out of such a broken JSON:
JSON.parse(JSON.stringify(obj)) // "{a: 1, b: 2, c: 3}"

Setting variables based off an object

I have an object which could include a mix of properties e.g.
{a: 1}, {b: 4}, {c: 2}, {a: 3, b: 1}
it will be a key with a count value next to it.
I'd like to set a bunch of variables depending on which key names are in the object, for instance:
aOnly = {a: 1}, mixOfAB = {a: 3, b: 1}
I'm using this logic in a function which will eventually return a string value. What's the best way to operate on this object, I tried using a switch but it didn't work so well. I could use a large number of if/else statements but is there something more neater?

You could do something like this:
vars = {}
function setVariable(obj) {
keys = Object.keys(obj)
name = keys.length == 1 ? keys[0] + 'Only' : 'mixOf' + keys.join('').toUpperCase()
vars[name] = obj
}
setVariable({a: 1})
console.log(vars)
setVariable({b: 4})
console.log(vars)
setVariable({c: 2})
console.log(vars)
setVariable({a: 3, b: 1})
console.log(vars)

String to Integer Object hashing in JavaScript

There are multiple questions here in SO that are similar to my question, but none really answers it completely.
Basically, I want to have objects as keys in JavaScript. I know it is possible with Map, however, it doesn't fully apply to my use-case. Here is the reason:
Let's say I have two objects, var d1 = {a: 1, b: 2} and var d2 = {a: 1, b: 2}, and a Map var m = new Map(). When adding d1 to m, when I call m.get(d2) I will get undefined. I assume it is because Map works in a reference-like manner.
However, I want the following functionality:
m.set(d1, 'hit');
m.get(d2) // should return 'hit' because properties and values of d1 = d2
One approach I thought of was not to use Map, but a simple JS object. Keys would be JSON.stringify(obj) and when I want to get a value from the object, I use JSON.parse(key) and then perform object equality check (Object.getOwnPropertyNames and then checking one-by-one).
However, I feel that this approach is way more complex and time-consuming than it should be. What I am looking for is probably a hash function of some sort that would efficiently map a object with keys of type String to values of type Number (integer in my case). Also, the ordering can be different (d1 = {a: 1, b: 2} should equal d2 = {b: 2, a: 1}).
How to design an efficient hash function to work with either JS Objects/Maps to perform the above-mentioned operations?

Write a function that turns the object into a string with the keys in a consistent order.
function objToKey(obj) {
Object.keys(obj).sort().map(k => `${k}:${obj[k]}`).join(',');
}
var d1 = {a: 1, b: 2},
d2 = {b: 2, a: 1},
m = new Map();
m.set(objToKey(d1), "foo");
console.log(m.get(objToKey(d2)));

Convert Object to string in javascript without the quotes in key

How can I convert an Object to a string so that output is something like this:
e.g. let a = {b: "c"}
Let's assume the above example is our sample Object. Now we can use JSON.stringify(a) to convert it to string but that outputs,
console.log(a) -> {"b": "c"} but I want something like this: {b: "c"} in the original Object format.

You can try using a Reg-ex, where you replace only the first occurrence of "" with white space character using $1 in the String.prototype.replace call:
const a = JSON.stringify({a: "a", b: "b", c: "c"}).replace(/"(\w+)"\s*:/g, '$1:');
console.log(a);

This code is taken from this answer.
There is a regex solution that is simpler but it has a shortcoming that is inherent to regex. For some edge cases in complex and nested objects it does not work.
const data = {a: "b", "b": "c",
c: {a: "b", "c": "d"}}
console.log(stringify(data))
function stringify(obj_from_json){
if(typeof obj_from_json !== "object" || Array.isArray(obj_from_json)){
// not an object, stringify using native function
return JSON.stringify(obj_from_json);
}
// Implements recursive object serialization according to JSON spec
// but without quotes around the keys.
let props = Object
.keys(obj_from_json)
.map(key => `${key}:${stringify(obj_from_json[key])}`)
.join(",");
return `{${props}}`;
}

You can try javascript-stringify npm package.

Join Array of Objects by Property using lodash

Is there a way using lodash or another library to join an array of objects?
I'm looking for a readymade function not a for loop.
For example:
[{a: 1}, {a:3}, {a: 4}]
//Run a function by specifing the property a and setting "," as the delimeter
Get 1,3,4

Here is your lodash answer
var arr = [{a: 1}, {a:3}, {a: 4}];
var s = _.map(arr, 'a').join(',');
//s == '1,2,3,4'

You don't need lodash for this, you can just use map and join:
let collection = [{a: 1}, {a:3}, {a: 4}];
alert(collection.map(item => item.a).join(','));