Variables in RegEx & Is this an acceptable use for DGraph

Users
6

Below is the full sample, the commented out option is the one that works. In both cases I am searching the same username “vespertilian” which is the only demo user I have loaded.

I did notice in the docs that there should be a minimum requirement setup for regex searching.

// function query(usernamePartialString: string): string {
//     return `query {
//         users(func: regexp(username, /${usernamePartialString}/))
//         {
//             uid
//             name
//             emailAddress
//             username
//             timezone
//             bio
//         }
//     }`;
// }

const query = `query all($a: string) {
        users(func: regexp(username, /$a/))
        {
            uid
            name
            emailAddress
            username
            timezone
            bio
        }
 };`

export async function usersUsernameResolver(
    _: any,
    {username} : any,
    context: any,
    info: any,
    dgraphClient: DgraphClient = newDgraphClient()
) {
    const vars = { $a: username};

    let result = null;
    try {
        // const res = await dgraphClient.newTxn().query(query(username));
        const res = await dgraphClient.newTxn().queryWithVars(query, vars);
        const jsonStr = new Buffer(res.getJson_asU8()).toString();
        result = JSON.parse(jsonStr).users;
        console.log(result)
    } catch(e) {
       console.log(e)
    }
    return result;
}