How to use regex to match object key and replace with its value?

Question

I'm still new with Javascript and I'm not entirely sure how to go about this.

I want it to match the key field and replace it with its value.

const state = {
"NY": "New York"
}

You live in NY to You live in New York

The list is going to be quite long with all the states so I think I'll have to use objects. Any help would be appreciated! Thank you in advance!

EDIT>>>

Thank you so much to those that replied! I made a list of all the states for USA, Canada, and Mexico to their full name here: https://gist.github.com/PepperAddict/b8c6c80af4a17908fd98378b4375047e

using the code that was provided, I was able to change them all to their full name.

Thank you thank you thank you!

Object.keys(state).forEach(k => str = str.replace(k, state[k])) — Ele
– Ele, Commented Apr 10, 2018 at 15:05

Ele · Accepted Answer · 2018-04-10 16:03:56Z

2

You don't need regex, use the keys from the object state

Object.keys(state).forEach(k => str = str.replace(k, state[k]));

const state = { "NY": "New York" };
var str = "You live in NY";

Object.keys(state).forEach(k => str = str.replace(k, state[k]));
console.log(str);

Using regex to replace the whole set of matches:

const state = { "NY": "New York" };
var str = "You live in NY and again in NY";

Object.keys(state).forEach(k => str = str.replace(new RegExp(`\\b${k}\\b`, 'g'), state[k]));
console.log(str);

edited Apr 10, 2018 at 16:03

answered Apr 10, 2018 at 15:07

Ele

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3 Comments

PepperAddict Over a year ago

Wow. This worked beautifully!!! I had a feeling I was overcomplicating this. Thank you!!!

jmcgriz Over a year ago

Only downside here is that it will only work with a single instance of each state. If it shows up more than once, the later instances will not be replaced. For that, you either need a while loop or regex

jmcgriz Over a year ago

I've added an answer that shows the regex solution that will handle all replacements

Joe Warner · Accepted Answer · 2018-04-10 15:16:29Z

1

We can make use of template literals and map it will return an array which you can then do what you want with.

const state = {
"NY": "New York"
}
console.log(Object.keys(state).map(s => `You live in ${state[s]}`))

If you're planning to do this with a user for example

const state = {
"NY": "New York"
}
const user = {
 name: "joe",
 state: "NY",
 liveIn: () => `You live in ${state[user.state]}`
}
console.log(user.liveIn())

answered Apr 10, 2018 at 15:16

Joe Warner

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Comments

jmcgriz · Accepted Answer · 2018-04-10 15:24:15Z

1

const states = {
  "CA": "California",
  "NY": "New York"
}

var input = "I'm from CA, thinking of moving to NY but not sure, I still really like CA."

var regexStr = Object.keys(states).join("|")
var statesRgx = new RegExp(`\\b(${regexStr})\\b`, 'g')
console.log(statesRgx)
function stateReplace(str){
  return str.replace(statesRgx, val => states[val])
}

console.log(stateReplace(input))

answered Apr 10, 2018 at 15:24

jmcgriz

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Comments

Sarvan Kumar · Accepted Answer · 2018-04-10 16:21:35Z

1

if you are sure the last word is key. Then you can skip foreach by following.

const state = {
"NY": "New York"
}

var a = "You live in NY";

b = a.split(" ");

b = b[b.length - 1];


a.replace(b, state[b]);

Console.log(a);

Output

"You live in New York"

edited Apr 10, 2018 at 16:21

Sarvan Kumar

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answered Apr 10, 2018 at 15:16

vichu

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