Merge pull request #187 from meetzaveri/patch-2

Create First-one-to-pass-truth-test.md
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Angelos Chalaris
2017-12-18 13:05:32 +02:00
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### First one to pass truth test
A function that looks through an array (first argument) and returns the first element in the array that passes a truth test (second argument).
```js
findElement = (arr, func) => {
filterArr = arr.filter(func); //filter array with the function provided
return filterArr[0]; //return the first element that returns true, or undefined if no elements return true
}
// findElement([1, 2, 3, 4], function(num){ return num !== 2 && num !== 1 }); //3 <- first element in array to be passed truth test
```

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### truthCheckCollection
Checks if the predicate (second argument) is truthy on all elements of a collection (first argument).
Use `Array.every()` to check if each passed object has the specified property and if it returns a truthy value.
```js
truthCheckCollection = (collection, pre) => (collection.every(obj => obj[pre]));
// truthCheckCollection([{"user": "Tinky-Winky", "sex": "male"}, {"user": "Dipsy", "sex": "male"}], "sex") -> true
```