How can I display data in mysql in web page? - mysql

Question

I am using nodejs and mysql to display several words in database in webpage with express.
I recently noticed that if I use SELECT inside of async/await, I can only use that data inside of it.
Therefore, I tried to do writeHead inside that function, but did not work.
Below is my code segments.
Could you please give me some advice?
const mysql = require('mysql2/promise');
const getData = async (lang, word) => {
try {
// db connection
var connection = await mysql.createConnection({
host: "-----",
user: "-----",
password: "-----",
database: "-----",
});
var [idA, fieldsA] = await connection.query(`SELECT id FROM en WHERE word=${"'"+word+"'"}`);
var [idB, fieldsB] = await connection.query(`SELECT id FROM ${lang} WHERE word=${"'"+word+"'"}`);
if(idA[0] === undefined && idB === undefined){
return null;
}else{
if(idB[0] === undefined) wordId = idA[0].id;
else wordId = idB[0].id;
var [dataA, fieldsA] = await connection.query(`SELECT * FROM en WHERE id=${"'"+wordId+"'"}`);
var [dataB, fieldsB] = await connection.query(`SELECT * FROM ${lang} WHERE id=${"'"+wordId+"'"}`);
if(lang === 'en' || dataB[0] === undefined){
[dataB, fieldsB] = await connection.query(`SELECT * FROM en WHERE id='null'`);
}
var data = [
{'id': dataA[0].id, 'word': dataA[0].word, 'def': dataA[0].def, 'syn': dataA[0].syn, 'ref': dataA[0].ref, 'area': dataA[0].area},
{'id': dataB[0].id, 'word': dataB[0].word, 'def': dataB[0].def, 'syn': dataB[0].syn, 'ref': dataB[0].ref, 'area': dataB[0].area}
];
return data;
}
} catch (error) {
console.log(error);
}
};
app.get('/search/:lang/:word', (req, res) => {
getData(req.params.lang, req.params.word)
.then((response) => {
console.log(response)
let page = templateSearch.getPage(response, req.params.lang, req.params.word);
res.writeHead(200);
res.end(page);
});
});