Access Object key based on Regex value in Javascript-CodePudding

I have a object like this

let obj = {'fruits_[apple,banana]':'This include Apple and Banana Both'}

But i only have apple as key to access

eg :: obj['fruits_\apple\] ---> this is not working

does anyone have idea how we can access key using regex??

CodePudding user response：

It depends how exact you want to be with your regex, but something like the below will work in the example given

const obj = {'fruits_[apple,banana]':'This include Apple and Banana Both'}


function findValue(obj, partialKey){
    var item = Object.entries(obj).find( ([k]) => {
      return k.match("fruits.*"   partialKey    ".*");
    });
    
    return item?.[1]
}

console.log(findValue(obj,"apple"));
console.log(findValue(obj,"banana"));
console.log(findValue(obj,"orange"));

Note that this will also work with partial key ban which may or may not be what is required. You need a more exact regex to only support whiole words.

CodePudding user response：

If you are the one responsible for creating obj, I suggest using 2 separate keys instead of one key that contains a list.

const obj = {
  fruits_apple:  "This include Apple and Banana Both",
  fruits_banana: "This include Apple and Banana Both",
};

This makes accessing the value as easy as obj[`fruits_${fruit}`] where fruit is a variable containing either "apple" or "banana".

This works best if you treat obj as immutable, because updating obj.fruits_apple will not automatically update obj.fruits_banana. So you are responsible for keeping the values in sync.

This can be easily addressed by wrapping the values in an object that acts as a reference.

const value = { value: "This include Apple and Banana Both" };
const obj = { fruits_apple: value, fruits_banana: value };

The above allows you to update both fruit_apple and fruits_banana at the same time, even if you only have access to a single fruit.

obj.fruits_apple.value = "Some new value";

Will also update obj.fruits_banana, since both refer to the same wrapper object.

const value = { value: "This include Apple and Banana Both" };
const obj = { fruits_apple: value, fruits_banana: value };

obj.fruits_apple.value = "Some new value";

console.log(obj.fruits_apple.value);
console.log(obj.fruits_banana.value);

This wrapper object is only needed if you plan to mutate the values though.