Doubt when using a Query answer in Nodejs

Question

Well, first, I have two files: index.js that handles the requests and another that selects in the database, but I don’t know how to return it to the client.

app.get('/pesqAlimentos', (req, res) => {
    pesqAlimentos(req.query.pesq.barraPesq);        
});

The code above is from index.js.

function pesqAlimento(string){
    let str = string.toLowerCase().
    client.connect();
    client.query("SELECT * FROM pesquisaAlimentos('?')", [str]).then(res => 
    // aqui que não sei como retorno para o index as rows de 
    resposta para o index.js).catch(e => console.log(e))    
}

This is the file where select is done. What I wanted is to be able to return res.Rows, or be able to send it as an answer already.

Answer 1

You already have a function that returns a promise, just use the await to unpack the result in this file, so you may not need callbacks and can simplify the code:

app.get('/pesqAlimentos', async (req, res) => {
    try {
        let rows = await pesqAlimentos(req.query.pesq.barraPesq);
        res.send(rows);
    } catch(err) {
        res.status(500).send(err);
    }      
});

async function pesqAlimento(string){
    let str = string.toLowerCase();
    client.connect();

    try {
        let res = await client.query("SELECT * FROM pesquisaAlimentos('?')", [str]);
        return res.rows;
    } finally {
        // Lembre de fechar a conexão. Um comando dentro do finally sempre 
        // irá rodar antes da função retornar ou lançar uma exceção
        client.close();
    }  
}

You will also need the modifier async in the functions they use await, if you’re not familiar with promises, inform yourself with the documentation here and here.