--- id: a10d2431ad0c6a099a4b8b52 title: Everything Be True isRequired: true challengeType: 5 --- ## Description <section id='description'> Check if the predicate (second argument) is <dfn>truthy</dfn> on all elements of a collection (first argument). In other words, you are given an array collection of objects. The predicate <code>pre</code> will be an object property and you need to return <code>true</code> if its value is <code>truthy</code>. Otherwise, return <code>false</code>. In JavaScript, <code>truthy</code> values are values that translate to <code>true</code> when evaluated in a Boolean context. Remember, you can access object properties through either dot notation or <code>[]</code> notation. Remember to use <a href='http://forum.freecodecamp.org/t/how-to-get-help-when-you-are-stuck/19514' target='_blank'>Read-Search-Ask</a> if you get stuck. Try to pair program. Write your own code. </section> ## Instructions <section id='instructions'> </section> ## Tests <section id='tests'> ```yml tests: - text: '<code>truthCheck([{"user": "Tinky-Winky", "sex": "male"}, {"user": "Dipsy", "sex": "male"}, {"user": "Laa-Laa", "sex": "female"}, {"user": "Po", "sex": "female"}], "sex")</code> should return true.' testString: 'assert.strictEqual(truthCheck([{"user": "Tinky-Winky", "sex": "male"}, {"user": "Dipsy", "sex": "male"}, {"user": "Laa-Laa", "sex": "female"}, {"user": "Po", "sex": "female"}], "sex"), true, ''<code>truthCheck([{"user": "Tinky-Winky", "sex": "male"}, {"user": "Dipsy", "sex": "male"}, {"user": "Laa-Laa", "sex": "female"}, {"user": "Po", "sex": "female"}], "sex")</code> should return true.'');' - text: '<code>truthCheck([{"user": "Tinky-Winky", "sex": "male"}, {"user": "Dipsy"}, {"user": "Laa-Laa", "sex": "female"}, {"user": "Po", "sex": "female"}], "sex")</code> should return false.' testString: 'assert.strictEqual(truthCheck([{"user": "Tinky-Winky", "sex": "male"}, {"user": "Dipsy"}, {"user": "Laa-Laa", "sex": "female"}, {"user": "Po", "sex": "female"}], "sex"), false, ''<code>truthCheck([{"user": "Tinky-Winky", "sex": "male"}, {"user": "Dipsy"}, {"user": "Laa-Laa", "sex": "female"}, {"user": "Po", "sex": "female"}], "sex")</code> should return false.'');' - text: '<code>truthCheck([{"user": "Tinky-Winky", "sex": "male", "age": 0}, {"user": "Dipsy", "sex": "male", "age": 3}, {"user": "Laa-Laa", "sex": "female", "age": 5}, {"user": "Po", "sex": "female", "age": 4}], "age")</code> should return false.' testString: 'assert.strictEqual(truthCheck([{"user": "Tinky-Winky", "sex": "male", "age": 2}, {"user": "Dipsy", "sex": "male", "age": 0}, {"user": "Laa-Laa", "sex": "female", "age": 5}, {"user": "Po", "sex": "female", "age": 4}], "age"), false, ''<code>truthCheck([{"user": "Tinky-Winky", "sex": "male", "age": 0}, {"user": "Dipsy", "sex": "male", "age": 3}, {"user": "Laa-Laa", "sex": "female", "age": 5}, {"user": "Po", "sex": "female", "age": 4}], "age")</code> should return false.'');' - text: '<code>truthCheck([{"name": "Pete", "onBoat": true}, {"name": "Repeat", "onBoat": true}, {"name": "FastFoward", "onBoat": null}], "onBoat")</code> should return false' testString: 'assert.strictEqual(truthCheck([{"name": "Pete", "onBoat": true}, {"name": "Repeat", "onBoat": true}, {"name": "FastFoward", "onBoat": null}], "onBoat"), false, ''<code>truthCheck([{"name": "Pete", "onBoat": true}, {"name": "Repeat", "onBoat": true}, {"name": "FastFoward", "onBoat": null}], "onBoat")</code> should return false'');' - text: '<code>truthCheck([{"name": "Pete", "onBoat": true}, {"name": "Repeat", "onBoat": true, "alias": "Repete"}, {"name": "FastFoward", "onBoat": true}], "onBoat")</code> should return true' testString: 'assert.strictEqual(truthCheck([{"name": "Pete", "onBoat": true}, {"name": "Repeat", "onBoat": true, "alias": "Repete"}, {"name": "FastFoward", "onBoat": true}], "onBoat"), true, ''<code>truthCheck([{"name": "Pete", "onBoat": true}, {"name": "Repeat", "onBoat": true, "alias": "Repete"}, {"name": "FastFoward", "onBoat": true}], "onBoat")</code> should return true'');' - text: '<code>truthCheck([{"single": "yes"}], "single")</code> should return true' testString: 'assert.strictEqual(truthCheck([{"single": "yes"}], "single"), true, ''<code>truthCheck([{"single": "yes"}], "single")</code> should return true'');' - text: '<code>truthCheck([{"single": ""}, {"single": "double"}], "single")</code> should return false' testString: 'assert.strictEqual(truthCheck([{"single": ""}, {"single": "double"}], "single"), false, ''<code>truthCheck([{"single": ""}, {"single": "double"}], "single")</code> should return false'');' - text: '<code>truthCheck([{"single": "double"}, {"single": undefined}], "single")</code> should return false' testString: 'assert.strictEqual(truthCheck([{"single": "double"}, {"single": undefined}], "single"), false, ''<code>truthCheck([{"single": "double"}, {"single": undefined}], "single")</code> should return false'');' - text: '<code>truthCheck([{"single": "double"}, {"single": NaN}], "single")</code> should return false' testString: 'assert.strictEqual(truthCheck([{"single": "double"}, {"single": NaN}], "single"), false, ''<code>truthCheck([{"single": "double"}, {"single": NaN}], "single")</code> should return false'');' ``` </section> ## Challenge Seed <section id='challengeSeed'> <div id='js-seed'> ```js function truthCheck(collection, pre) { // Is everyone being true? return pre; } truthCheck([{"user": "Tinky-Winky", "sex": "male"}, {"user": "Dipsy", "sex": "male"}, {"user": "Laa-Laa", "sex": "female"}, {"user": "Po", "sex": "female"}], "sex"); ``` </div> </section> ## Solution <section id='solution'> ```js function truthCheck(collection, pre) { // Does everyone have one of these? return collection.every(function(e) { return e[pre]; }); } ``` </section>