--- id: a10d2431ad0c6a099a4b8b52 title: Everything Be True isRequired: true challengeType: 5 --- ## Description
Check if the predicate (second argument) is truthy on all elements of a collection (first argument). In other words, you are given an array collection of objects. The predicate pre will be an object property and you need to return true if its value is truthy. Otherwise, return false. In JavaScript, truthy values are values that translate to true when evaluated in a Boolean context. Remember, you can access object properties through either dot notation or [] notation. Remember to use Read-Search-Ask if you get stuck. Try to pair program. Write your own code.
## Instructions
## Tests
```yml tests: - text: 'truthCheck([{"user": "Tinky-Winky", "sex": "male"}, {"user": "Dipsy", "sex": "male"}, {"user": "Laa-Laa", "sex": "female"}, {"user": "Po", "sex": "female"}], "sex") 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, ''truthCheck([{"user": "Tinky-Winky", "sex": "male"}, {"user": "Dipsy", "sex": "male"}, {"user": "Laa-Laa", "sex": "female"}, {"user": "Po", "sex": "female"}], "sex") should return true.'');' - text: 'truthCheck([{"user": "Tinky-Winky", "sex": "male"}, {"user": "Dipsy"}, {"user": "Laa-Laa", "sex": "female"}, {"user": "Po", "sex": "female"}], "sex") 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, ''truthCheck([{"user": "Tinky-Winky", "sex": "male"}, {"user": "Dipsy"}, {"user": "Laa-Laa", "sex": "female"}, {"user": "Po", "sex": "female"}], "sex") should return false.'');' - text: '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") 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, ''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") should return false.'');' - text: 'truthCheck([{"name": "Pete", "onBoat": true}, {"name": "Repeat", "onBoat": true}, {"name": "FastFoward", "onBoat": null}], "onBoat") should return false' testString: 'assert.strictEqual(truthCheck([{"name": "Pete", "onBoat": true}, {"name": "Repeat", "onBoat": true}, {"name": "FastFoward", "onBoat": null}], "onBoat"), false, ''truthCheck([{"name": "Pete", "onBoat": true}, {"name": "Repeat", "onBoat": true}, {"name": "FastFoward", "onBoat": null}], "onBoat") should return false'');' - text: 'truthCheck([{"name": "Pete", "onBoat": true}, {"name": "Repeat", "onBoat": true, "alias": "Repete"}, {"name": "FastFoward", "onBoat": true}], "onBoat") should return true' testString: 'assert.strictEqual(truthCheck([{"name": "Pete", "onBoat": true}, {"name": "Repeat", "onBoat": true, "alias": "Repete"}, {"name": "FastFoward", "onBoat": true}], "onBoat"), true, ''truthCheck([{"name": "Pete", "onBoat": true}, {"name": "Repeat", "onBoat": true, "alias": "Repete"}, {"name": "FastFoward", "onBoat": true}], "onBoat") should return true'');' - text: 'truthCheck([{"single": "yes"}], "single") should return true' testString: 'assert.strictEqual(truthCheck([{"single": "yes"}], "single"), true, ''truthCheck([{"single": "yes"}], "single") should return true'');' - text: 'truthCheck([{"single": ""}, {"single": "double"}], "single") should return false' testString: 'assert.strictEqual(truthCheck([{"single": ""}, {"single": "double"}], "single"), false, ''truthCheck([{"single": ""}, {"single": "double"}], "single") should return false'');' - text: 'truthCheck([{"single": "double"}, {"single": undefined}], "single") should return false' testString: 'assert.strictEqual(truthCheck([{"single": "double"}, {"single": undefined}], "single"), false, ''truthCheck([{"single": "double"}, {"single": undefined}], "single") should return false'');' - text: 'truthCheck([{"single": "double"}, {"single": NaN}], "single") should return false' testString: 'assert.strictEqual(truthCheck([{"single": "double"}, {"single": NaN}], "single"), false, ''truthCheck([{"single": "double"}, {"single": NaN}], "single") should return false'');' ```
## Challenge 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"); ```
## Solution
```js function truthCheck(collection, pre) { // Does everyone have one of these? return collection.every(function(e) { return e[pre]; }); } ```