CODEWITHSUNDEEP
javascript
İspik
İspik

Reputation: 21

JavaScript replace tokens in curly braces

So my previous question was pretty bad so I am editing this question.

I have object/json like this

{
"title": "Hello {USER}",
"description": "Today you earned {AMOUNT} dolars
}

I'm sending this data to api so it gives returns an special message. But the problem is I need to replace {USER} and {AMOUNT} without needing to get values, change it and reassign it or etc. It's like replace but for objects so without changing object and doing complicated things I can dynamicly change {USER} and {AMOUNT} User comes from the api and AMOUNT is a random number I just need to change the {} brackets without complicating things too much

Upvotes: 0

Views: 2081

Answers (3)

Wyck
Wyck

Reputation: 11750

Here's an approach that uses a regular expression to locate {KEY} and looks up KEY in a dictionary to perform the replacement. I used a conservative syntax of A-Z plus underscore for the syntax of the key names.

This version returns a new object (does not change the original object).

function interpolateObject(obj, dict) {
  return Object.fromEntries(Object.entries(obj).map(interpolateEntry));
}

function interpolateEntry([key, val]) {
  if (typeof val !== 'string') return [key, val];
  return [key, interpolateString(val, dict)];
}

function interpolateString(str, dict) {
  return str.replace(/\{([A-Z_]+)\}/g, (original, key) => dict.hasOwnProperty(key) ? dict[key] : original);
}

const template = {
  "title": "Hello {USER}",
  "status": "You look {STATUS} today",
};
const dict = { USER: 'Mark', STATUS: 'great' };
console.log(interpolateObject(template, dict));

You could also write a version that modifies the object in-place if that's what's needed.

// Alternate approach, modifies object in place.
function interpolateObjMutate(obj, dict) {
  for (const key in obj) {
    if (typeof obj[key] === 'string') obj[key] = interpolateString(obj[key], dict);
  }
}

Upvotes: 2

lissettdm
lissettdm

Reputation: 13078

You can use a regex to replace the text in curly braces :

function replaceText(text, value) {
  const regex = /\{.*\}/;
  return text.replace(regex, value);
}

const TEXT = 'Hello {USER}';
console.log(replaceText(TEXT, 'Mark'));

Upvotes: 1

Spectric
Spectric

Reputation: 31992

String.prototype.replaceAll()

Returns

a new string, with all matches of a pattern replaced by a replacement.

var obj = {
"title": "Hello {USER}",
"status": "You look {STATUS} today"
};
function replaceTokens(name, value, str){
  return str.replaceAll("{"+name+"}", value);
}
obj.title = replaceTokens("USER", "Mark", obj.title);
obj.status = replaceTokens("STATUS", "great", obj.status);
console.log(obj);

Upvotes: 2

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