In Javascript, I am processing some JSON data that takes the form:

o = {
  a: null,
  b: null,
  c: 1,
  d: null
  // ... 10 or so other properties that are either null or numerical
}

I'm trying to write a quick function that will process the whole object to determine if there are any non-null values for any of the keys. Any suggestions to do this efficiently and with just a few lines of code? My project already uses underscore.js, so if that can speed things up or make it briefer, all the better.

In Javascript, I am processing some JSON data that takes the form:

o = {
  a: null,
  b: null,
  c: 1,
  d: null
  // ... 10 or so other properties that are either null or numerical
}

I'm trying to write a quick function that will process the whole object to determine if there are any non-null values for any of the keys. Any suggestions to do this efficiently and with just a few lines of code? My project already uses underscore.js, so if that can speed things up or make it briefer, all the better.

• javascript
• underscore.js

3 Answers 3

What about the one-liner,

_.any(_.values(a), function (v) { return !_.isNull(v) });

which will return true if there is at least one non-null value.

var hasVal = false;
for (var prop in obj) {
    hasVal = obj.hasOwnProperty(prop) && obj[prop] !== null;
    if (hasVal) break;
}

You could use _.find in bination with _.isNull:

var has_a_null = _.chain(o).find(_.isNull).isNull().value();

or similarly:

var has_a_null = _(o).find(_.isNull) === null

Demo: http://jsfiddle/ambiguous/t678w/