Foreach to Variable Javascript / React

February 24, 2022

i want to ask something about how to join data inside variable, so basicly I have data that I foreach (because i need to change that object), then I want to enter each data that I foreach into a variable, as below:

const thisData = {["abcd","efgh"]}
for (let objData of thisData) {
    //lets say i need to change every data from word to number
    //I've managed to change it
    const newData = changetoNumber(objData)
}

then i need to save it to another variable, and now i’m stuck, can you guys help me?

//this is what i need
console.log(listnewData)
//1234 5678

>Solution :

You are looking for a "map".

So, the map method takes in a single parameter, a function which is called on each item, in the simplest case with a single parameter, the item itself like so:


function f(x) {
    return x.length // for example
}

const thisdata = ["abcd", "efg"];
const newvar = thisdata.map(f);
console.log(newvar); // prints [3,2]