To turn all the keys of an object to lower case with JavaScript, we use some object methods.
For instance, we write
const newObj = Object.fromEntries(
Object.entries(obj).map(([k, v]) => [k.toLowerCase(), v])
);
to call Object.entries to return an array of key-valye pair arrays from the obj.
Then we call map with a callback to map the keys to lower case with toLowwerCase and v.
And then we call Object.fromEntries to convert the mapped key-value pair array back to an object.
