JSFiddle - React, Tailwind, and code Playground
JavaScript
/* input: microSoftTeams
output: micro_soft_teams */
function converter(string){
let arr = [];
for (i=0;i<string.length;i++){
if(string[i].toLowerCase()!==string[i]){
arr.push('_', string[i].toLowerCase());
} else {
arr.push(string[i])
}
}
console.log(arr.join(''));
}
converter('microSoftTeams');