JSFiddle - React, Tailwind, and code Playground

JavaScript

var mapping = [     //response.mapping
    ["userOne", 1],
    ["userTwo", 2],
    ["userthree", 3],
    ["userfour", 4],

    ["personOne", 1],
    ["personTwo", 2],
    ["personOne", 3],
];
var findIndex = function (hayStack, needle) {
    for (var i = 0; i < hayStack.length; i++) {
        if(hayStack[i][0] === needle[0] && hayStack[i][1] === needle[1]) {
            return i;
        }
    }
    return -1;
};
var captured_list_elm = ["personOne", 1];
var status = findIndex(mapping, captured_list_elm);
alert("status= "+status);