JSArrayFilter

jsarrayfilter.markdown

JSArrayFilter

A Pen by Amanda on CodePen.

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script.js

/*
Write a function called filterByValue which accepts an array of objects and a key and returns a new array with all the objects that contain that key.

Examples:
    filterByValue([{first: 'Elie', last:"Schoppik"}, {first: 'Tim', last:"Garcia", isCatOwner: true}, {first: 'Matt', last:"Lane"}, {first: 'Colt', last:"Steele", isCatOwner: true}], 'isCatOwner') // [{first: 'Tim', last:"Garcia", isCatOwner: true}, {first: 'Colt', last:"Steele", isCatOwner: true}]
*/

function filterByValue(arr, key){
  return arr.filter(function(value){
		return key in value;	
	});
}

/*
Write a function called find which accepts an array and a value and returns the first element in the array that has the same value as the second parameter or undefined if the value is not found in the array.

Examples:
    find([1,2,3,4,5], 3) // 3
    find([1,2,3,4,5], 10) // undefined
*/

function find(arr, searchValue){
	var fArr = arr.filter(function(value){
		return value === searchValue;	
	});    
	if (fArr.length>0) return fArr[0];
}

/*
Write a function called findInObj which accepts an array of objects, a key, and some value to search for and returns the first found value in the arrayt.

Examples:
    findInObj([{first: 'Elie', last:"Schoppik"}, {first: 'Tim', last:"Garcia", isCatOwner: true}, {first: 'Matt', last:"Lane"}, {first: 'Colt', last:"Steele", isCatOwner: true}], 'isCatOwner',true) // {first: 'Tim', last:"Garcia", isCatOwner: true}
*/

function findInObj(arr, key, searchValue){
    var newArr =arr.filter(function(value){
		return key in value && value[key] === searchValue;	
	});
	if (newArr.length > 0) return newArr[0];
}

/*
Write a function called removeVowels which accepts a string and returns a new string with all of the vowels (both uppercased and lowercased) removed. Every character in the new string should be lowercased.

Examples:
    removeVowels('Elie') // ('l')
    removeVowels('TIM') // ('tm')
    removeVowels('ZZZZZZ') // ('zzzzzz')
*/

function removeVowels(str){
	var arr = str.split('');
	var vowels = ['a','e','i','u'];
	return arr.filter(function(value){
		return vowels.indexOf(value.toLowerCase()) === -1;	
	}).join('').toLowerCase();
}

/*
Write a function called doubleOddNumbers which accepts an array and returns a new array with all of the odd numbers doubled (HINT - you can use map and fitler to double and then filter the odd numbers).

Examples:
    doubleOddNumbers([1,2,3,4,5]) // [2,6,10]
    doubleOddNumbers([4,4,4,4,4]) // []
*/

function doubleOddNumbers(arr){
    return arr.filter(function(value){
						return value%2 !==0;	
					}).map(function(val){
							return val*2;
		});
}