Test if any item in array returns true?

Question

I have an array of objects, currently I loop throught them and test them one by one, but I try to make my code more concice and easy to follow. I wonder weather there is a way, with javascript or underscore, to test if at least one item in array returns true.

  for (var x = 0; x < user.apilog.length; x++) {
    //test the conversion
    if(conversions[i].conditional(user.apilog[x]) ){
      //run if true
      break;
    }
  }

JLRishe · Accepted Answer · 2014-12-09 13:38:57Z

1

If user.apilog is an array, then you can use Array.prototype.some():

var found = user.apilog.some(function (item, i) {
    return conversions[i].conditional(item);
});

n.b. underscore also provides a some method that works pretty much the same way, with the benefit that it should work on array-like objects as well as actual arrays:

var found = _.some(user.apilog, function (item, i) {
    return conversions[i].conditional(item);
});

edited Dec 9, 2014 at 13:38

answered Dec 9, 2014 at 13:29

JLRishe

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3 Comments

Himmators Over a year ago

Wow! that is sweet! I don't need IE8 support and I bet this will have better perfomance than something like underscore!

brianforan Over a year ago

I didn't know about this before but couldn't you he just create a function check(elem, index, arr) and then call user.apilog.some(check)? edit: assuming the function checked if true or false

JLRishe Over a year ago

@pbrianq Yes, defining the function separately would certainly work, too. I'm using an anonymous function here because it's just a one-line function and defining it as a separate function might be overkill.

u.k · Accepted Answer · 2014-12-10 11:29:27Z

0

With underscore.js you could simply use _.some(user.apilog)

answered Dec 10, 2014 at 11:29

u.k

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