How to change blank fields to null in express js

Question

I want to get all request body params as null if param is blank. Is there any way in the express js.

{
  username: " ",
  password: ""
}

// Get it as

{
  username: null,
  password: null
}

Answer 1

Maybe you want to use this function below:

let objects = {
    username: ' ',
    password: '',
    testing: [
      {
        id: ' ',
        testing: 'testing'
      }
    ],
    obj: {
      key: ' ',
      value: 'value'
    }
}

function setEmptyToNull(obj) {
    Object.keys(obj).forEach(key => {
        if (Array.isArray(obj[key])) {
            obj[key].map(o => {
                if (typeof o === 'object') {
                    setEmptyToNull(o);
                }
            })
        } else if(typeof obj[key] ==='string') {
          if(obj[key].trim() === '') {
            obj[key] = null;
          }  
        } else if(typeof obj[key] === 'object') {
          setEmptyToNull(obj[key]);
        }
    });
    return obj;
}

console.log(setEmptyToNull(objects));

Now, if you want to use in your express application, then you can set that function in your custom middleware. It's will looks like this code below:

app.use((req, res, next) => {
  if(req.body) {
    setEmptyToNull(req.body);
  };
  next();
});

After you set your custom middleware, now each value of key in your req.body, if it's ' ' then will be set to null.

I hope it can help you.