Convert JS object to TS type

getType.js

function getType(x) {
    let type = typeof x;
    if (type === 'object') {
        if (Array.isArray(x)) {
            return `Array<${getType(x[0])}>`;
        } else {
            let fields = [];
            for (let key of Object.keys(x)) {
                fields.push(`${key}: ${getType(x[key])}`);
            }
            return `{${fields.join(', ')}}`;
        }
    } else {
        return type;
    }
}