Date formatting error in Android in React native

I am getting value like 202001.

I want to covert it like January_2020.

Is there a way to convert it like this?:

202001->January_2020

i tried to do this by using Intl and it is working fine for ios but not working in android.

i tried below one.

const dateToStr = (input) => {
    if (input.length !== 6) {
      return "wrong date syntax, use YYYYMM";
    }
    const parts = input.match(/([0-9]{4})([0-9]{2})/);
    if (!parts) {
      return "wrong date syntax, use YYYYMM";
    }
    // NOTE: check syntax of parts
    const formatter = new Intl.DateTimeFormat("en-EN", { month: "long" })
      .format;
    const formatted = formatter(
      new Date(Date.UTC(parseInt(parts[1]), parseInt(parts[2]) - 1))
    );

    return `${formatted}_${parts[1]}`;
  };

How can i get this updated value in Javascript without using any library in android and ios both?