truthy

comparative truthier · superlative truthiest

1. humorousobsoleteFaithful; true.First known use 19th c.

   You […] are afraid Theodore your sweetheart shouldn't prove truthy.

   c. 1800, J. H. Colls, Theodore

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   Mindy Lahiri is never one to mince words, and most of the things that come out of her mouth are rife for a gospel. But her sheer overwhelming emotion at her doughnut craving is one of the truthiest truthisms she's ever truthed. Preach, girl.

   2016 June 3, Seija Rankin, “It's National Doughnut Day, so Let's Relive the Best Doughnut Moments in Pop Culture”, in E! Online

   Synonyms: faithful, honest

2. UScolloquialOnly superficially true; that is asserted or felt instinctively to be true, with no recourse to facts.First known use 21st c.

   Historians today point out that each of these ringing assertions was, at best, truthy.

   2011, Steven Pinker, The Better Angels of Our Nature, Penguin, published 2012, page 595

   Synonyms: truthlike, truthful, truthsome, veridical

3. computingEvaluating to true in a Boolean context.

   In JavaScript, as well as the true or false Boolean values, other types of variables can be said to be truthy or falsey.

   2013, Dan Wellman, jQuery Hotshot, →ISBN

   3 more examples

   In JavaScript, any expression or statement that expects a boolean value will work with a truthy or falsy value, so the fact that && does not always evaluate to true or false does not cause practical problems.

   2012, David Flanagan, JavaScript Pocket Reference, page 40

   To remember which values are truthy and which are falsey, just memorize the five falsey values - undefined, null, 0, "" and NaN -- and remember that everything else is truthy.

   2014, Eric T. Freeman, Elisabeth Robson, Head First JavaScript Programming: A Brain-Friendly Guide, →ISBN, page 292

   Clojure uses the Boolean operators or and and. or returns either the first truthy value or the last value, and returns the first falsey value or, if no values are falsey, the last truthy value.

   2015, Daniel Higginbotham, Clojure for the Brave and True, →ISBN, page 40

   Antonyms: falsy