Loop through a Javascript Object values when its key matches specific string

Question

I have a function that loops through an Object's keys until the key matches a keyword within the input. After finding a match, how can I then loop through the matched Object keys values ?

let obj = {
  music: {
    "do you like music": "Yes I do",
    "what music do you like": "Jazz"
  },

  sports: {
    "Do you like sports": "Yes"
  }
};

let input = "i like music";

function run(input) {
  let newStr = input.split(' ');
  let key = Object.keys(obj);
  key.forEach((key) => {
    newStr.forEach((str) => {
      if (key === str) {
        console.log(key)
      }
    });
  });
};

run(input);

For future reference, that's what the "tidy" button on the Stack Snippet modal is for :) — Patrick Roberts
– Patrick Roberts, Commented Nov 24, 2018 at 17:39
Seems like arrays would make more sense for nested objects rather than using unique object keys — charlietfl
– charlietfl, Commented Nov 24, 2018 at 17:40
Why not if(str in obj) and then just log the str since it is the same as the key, no loops needed. — CME64
– CME64, Commented Nov 24, 2018 at 17:53
Thanks Patrick for the tip (: Also I used str in obj and it achieved what I was looking for — Swink
– Swink, Commented Nov 25, 2018 at 5:41

Nitish Narang · Accepted Answer · 2018-11-24 17:39:56Z

1

You can use Array.flatMap and return matching word value from obj

I assumed you would want to return entire value for matching key

let obj = {
  	music:{
    	"do you like music":"Yes I do",
      "what music do you like": "Jazz"
    },
    
    sports:{
    	"Do you like sports": "Yes"
    }
};

function run(i) {
  return i.split(' ').flatMap(d => obj[d] || [])[0]
}

console.log(run("i like music"))

console.log(run("i like sports"))

answered Nov 24, 2018 at 17:39

Nitish Narang

4,2042 gold badges17 silver badges22 bronze badges

Sign up to request clarification or add additional context in comments.

12 Comments

charlietfl Over a year ago

Should also note that flatMap does not have broad browser support and would require polyfill

Nitish Narang Over a year ago

@charlietfl That’s correct. If you don’t mind me asking one thing.. i am developing myself technically and learning from you all by viewing your answers.. and understanding those. flatMap is also one of those features i learnt from SO but when i dont use it I get comment that i should use that and when I use it I get comment its not much supported.. pls can you advice if I should use it or dont prefer it Or shall always mention that it needs polyfill?. 😊 Thank you.

charlietfl Over a year ago

It does get tricky these days though so i understand the confusion. If developing only in node and not front end feature support isn't as much of an issue. ES6 features for front end where not using transpiler or for methods that aren't supported in legacy browsers does get complicated

slider Over a year ago

Yes, but you can simply add a filter before map to only consider keys that are in obj and that should solve the problem. The real purpose of flatMap is to flatter a 2d array after map is applied but in this case you don't have a 2d array at all.

Nitish Narang Over a year ago

I believe if you use node version > 8 then it won't be any problem to you. @JimCiaston

|

Collectives™ on Stack Overflow

Loop through a Javascript Object values when its key matches specific string

1 Answer 1

12 Comments

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

1 Answer 1

12 Comments

Your Answer

Sign up or log in

Post as a guest

Related