Validate object's value

Question

I have an JavaScript object with keys and values. I need to validate that object's values, and if it contains value 'empty', I want to give an alert. I want to give alert only once even if there were multiple 'empty' values.

I tried like this;

data = [
  {first_name: 'John', last_name: 'Doe'},
  {first_name: 'Kiki', last_name: 'empty'},
  {first_name: 'Kim', last_name: 'empty'},
]

data.forEach(function(value){
  if(value.last_name == 'empty'){
    alert('Please fill all the field');
    return false;
  }
});

This could validate the value, but it's giving alert twice.

I want to show alert only once. How can I do this?

Jack Bashford · Accepted Answer · 2019-04-08 01:43:37Z

Use some:

const data = [{
    first_name: 'John',
    last_name: 'Doe'
  },
  {
    first_name: 'Kiki',
    last_name: 'empty'
  },
  {
    first_name: 'Kim',
    last_name: 'empty'
  },
];

if (data.some(e => Object.values(e).some(f => f == "empty"))) {
  alert("There is an empty value");
}

If you want to show the other data as well (like which property in which index), you could use the other parameters in the callback function:

const data = [{
    first_name: 'John',
    last_name: 'Doe'
  },
  {
    first_name: 'Kiki',
    last_name: 'empty'
  },
  {
    first_name: 'Kim',
    last_name: 'empty'
  },
];

if (data.some(e => Object.values(e).some(f => f == "empty"))) {
  let index = data.findIndex(e => Object.values(e).some(f => f == "empty"));
  let [property] = Object.entries(data[index]).find(([k, v]) => v == "empty");
  alert(`The property ${property} at index ${index} is empty.`);
}

Thank you so much! The second code improved my program a lot!

Ele · Accepted Answer · 2019-04-08 01:41:19Z

1

You can use the function some to check if at least one object's last_name === 'empty'

const data = [{first_name: 'John',last_name: 'Doe'},{first_name: 'Kiki',last_name: 'empty'  },{first_name: 'Kim',last_name: 'empty'}];

// The function some returns true 
// if at least one object meets the predicate 'last_name === "empty"'.
if (data.some(({last_name}) => last_name === "empty")) alert("There is an empty value");

answered Apr 8, 2019 at 1:41

Ele

33.8k7 gold badges43 silver badges80 bronze badges

Comments

Yoko Ishioka · Accepted Answer · 2019-04-08 01:39:40Z

0

It's giving you the alert twice, once for Kiki and once for Kim. If you want to stop the loop after the first occurrence, you need to change "return false" to "break" like this:

data.forEach(function(value){
  if(value.last_name == 'empty'){
    alert('Please fill all the field');
    break;
  }
});

answered Apr 8, 2019 at 1:39

Yoko Ishioka

1615 bronze badges

1 Comment

Yoko Ishioka Over a year ago

Also, your JSON would come back with null if it were empty instead of a string that says empty like in your example. So, your example is checking for someone who has the last name 'empty' instead of someone who left it blank.

Omolayo Victor · Accepted Answer · 2019-04-08 01:54:21Z

I think a loop can be handy in this kind of situation

let data = [
  {first_name: 'John', last_name: 'Doe'},
  {first_name: 'Kiki', last_name: 'empty'},
  {first_name: 'Kim', last_name: 'empty'},
]

// data.forEach(function(value){
//   if(value.last_name == 'empty'){
//     alert('Please fill all the field');
//     return false;
//   }
// });

for(let i of data) {
  if(i.last_name == "empty") {
    alert('Please fill all the field');
    break;
  }
}

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