javascript - How to determine if any values in an object are non-null? - Stack Overflow

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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

Share Improve this question Follow edited Jun 21, 2012 at 6:51 Yi Jiang 50.2k1616 gold badges139139 silver badges136136 bronze badges asked Jun 21, 2012 at 5:36 B RobsterB Robster 42.1k2424 gold badges9292 silver badges124124 bronze badges

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3 Answers 3

Sorted by: Reset to default 5

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/

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