Tips for locating a key within an object that houses a specific value in its array

Question

Tips for locating a key within an object that houses a specific value in its array

In my Coffeescript code, I have created the following Javascript object:

urlSets =
  a: [
    'url-a.com'
    'url-b.com'
    'url-c.com'
    ]
  b: [
    'url-d.com'
    'url-e.com' 
    'url-f.com'
    ]
  c: [
    'url-g.com'
  ]

If I have the value "url-a.com", how can I determine the key</cde> in <code>urlSets that contains this URL?

I am currently using the underscore.js library, and I thought about using _.findKey along with _.contains. My attempt looks like this:

_.findKey urlSets, (key) ->
  return _.contains(key, "url-a.com")

However, this approach is not working as expected and results in a

TypeError: undefined is not a function

.

javascript arrays coffeescript underscore.js javascript-objects

Answer 1

Answer №1

Personally, I prefer not relying on any external libraries when it comes to looping through data, especially with the convenience of CoffeeScript's loops.

foundKey = null

for key, urls of urlSets
  if 'url-a.com' in urls
    foundKey = key

console.log foundKey #=> a

This code snippet utilizes a for key, value of object loop to easily iterate through the urlSets object and then performs an if item in array check which CoffeeScript compiles into an indexOf call.

Answer 2

Personally, I prefer not relying on any external libraries when it comes to looping through data, especially with the convenience of CoffeeScript's loops.

foundKey = null

for key, urls of urlSets
  if 'url-a.com' in urls
    foundKey = key

console.log foundKey #=> a

This code snippet utilizes a for key, value of object loop to easily iterate through the urlSets object and then performs an if item in array check which CoffeeScript compiles into an indexOf call.

Answer 3

Answer №2

Your attempt to implement an iteration over an object has been made...

 let car = {make:"Toyota", model:"Camry", year:2022};

 for (let key in car) {
    console.log("car." + key + " = " + car[key]);
 }

To learn more about this concept, please visit: https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Statements/for...in

Answer 4

Your attempt to implement an iteration over an object has been made...

 let car = {make:"Toyota", model:"Camry", year:2022};

 for (let key in car) {
    console.log("car." + key + " = " + car[key]);
 }

To learn more about this concept, please visit: https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Statements/for...in

Tips for locating a key within an object that houses a specific value in its array

Answer №1

Answer №2

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