budibase/packages/client/src/api/authenticate.js

export const USER_STATE_PATH = "_bbuser";

export const authenticate = (api) => async ({username, password}) => {

    if(!username) {
        api.error("Authenticate: username not set");
        return;
    }  
    
    if(!password) {
        api.error("Authenticate: password not set");
        return;
    } 

    const user = await api.post({
        url:"/api/authenticate",
        body : {username, password}
    });

    // set user even if error - so it is defined at least
    api.setState(USER_STATE_PATH, user);
    localStorage.setItem("budibase:user", JSON.stringify(user));
}