How to Return Blank String If Object Is Undefined in Angularjs Forms

check null,empty or undefined angularjs

just use -

if(!a) // if a is negative,undefined,null,empty value then...
{
    // do whatever
}
else {
    // do whatever
}

this works because of the == difference from === in javascript, which converts some values to "equal" values in other types to check for equality, as opposed for === which simply checks if the values equal. so basically the == operator know to convert the "", null, undefined to a false value. which is exactly what you need.

If value is 0 then return empty string in Angularjs

You can do it like this:

{{profileCtrl.person.year === 0 ? "" : profileCtrl.person.year}}

How do I check for an empty/undefined/null string in JavaScript?

Empty string, undefined, null, ...

To check for a truthy value:

if (strValue) {
    // strValue was non-empty string, true, 42, Infinity, [], ...
}

To check for a falsy value:

if (!strValue) {
    // strValue was empty string, false, 0, null, undefined, ...
}

---

Empty string (only!)

To check for exactly an empty string, compare for strict equality against "" using the === operator:

if (strValue === "") {
    // strValue was empty string
}

To check for not an empty string strictly, use the !== operator:

if (strValue !== "") {
    // strValue was not an empty string
}

AngularJS - What is the best way to detect undefined null or empty value at the same time?

Update

As mentioned in the comments it's better to use return !value.

$scope.isValid = function(value) {
    return !value
}

Old and incomplete Answer

A proper way is simply to use angular.isDefined()

How to display empty string when ng-repeat value is null in angularjs

Zero is falsy. Use ternary operator:

{{ x.daysSinceMaintenanceUpdate == null ? '--' : x.daysSinceMaintenanceUpdate }}

---

Related Topics