// Array :- It is collection more the single value inside an variable // concat :- It return a new array by merging two or more than two arrays. // e.g. merged only two arrays const lang1 = ["python","java"]; const lang2 = ["c++","javascript","react"]; const output = lang1.concat(lang2); console.log(output);//It only create new array and not change the original arrays console.log(lang1);//not change just like me console.log(lang2);//as it is