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_.identity = function(value){
// return value
return value;
}
_.typeOf = function(value){
if (typeof value === "string"){ // tests if value is a string
return "string"; // returns "string"
} else if (typeof value === "boolean"){ // tests if value is a boolean
return "boolean"; // returns "boolean"
} else if (typeof value === "number"){ // tests if value is a number
return "number"; // returns "number"
} else if (typeof value === "undefined"){ // tests if value is undefined
return "undefined"; // returns "undefined"
} else if (typeof value === "function"){ // tests if value is a function
return "function"; // returns "function"
} else if (value === null){ // tests if value is null
return "null"; // returns "null"
} else{ // any other condition
if (Array.isArray(value)){ // tests if value is an array
return "array"; // returns array
} else { // any other object
return "object"; // returns "object"
}
}
}
_.first = function(arr, num){
if (!Array.isArray(arr) || num < 0){ // tests if arr is not an array
return []; // returns an empty array
} else{ // else, arr is an array
if (num === undefined){ // tests if num is not passed
return arr[0]; // returns first element of array
} else { // else, array is array and num is passed
return arr.slice(0, num);// return the first num elements of the array
}
}
}
_.last = function(arr, num){
if (!Array.isArray(arr) || num < 0){ // tests if arr is an array OR num is negative
return []; // returns empty array
} else { // else, arr is an array
if (num === undefined){ // tests if num is passed
return arr[arr.length - 1]; // if true, returns the last element of the array
} else if (num > arr.length){ // tests if num is greater than the length of array
return arr; // returns whole arr
} else { // else, num is passed
return arr.slice(arr.length - num); // returns the last num elements of the array
}
}
}
_.indexOf = function(arr, val){
for (var i = 0; i < arr.length; i ++){// iterate through arr
if (arr[i] === val){// test if current element is val
return i;// if true, return element index
}
}
return -1; // return -1 in outermost code block
}
_.contains = function(array, value){
// tests if array includes value. Returns true if true, false if false
return (array.includes(value)? true : false);
}
_.each = function(collection, func){
if (Array.isArray(collection)){ // tests if collection is an array
for (var i = 0; i < collection.length; i++){ // iterate through array
func(collection[i], i, collection) // call function for each element, index, and collection
}
} else { // else it's an object
for (var key in collection){ // iterate through object
func(collection[key], key, collection) // call function for each property value, key, collection
}
}
}
_.unique = function(array){
let newArr = []; // initialize newArr array
for (var i = 0; i < array.length; i++){ // iterate through array
if (newArr.indexOf(array[i]) === - 1){ // tests if newArr does not contain current iteration element
newArr.push(array[i]); // push current element into newArr
}
}
return newArr; // returns newArr
}
_.filter = function(array, func){
var newArray = []; // initialize newArray with value of empty of array
for (var i = 0; i < array.length; i++){ // iterate over array
if (func(array[i], i, array)){ // test if passing element, index, and array returns true
newArray.push(array[i]); // if true, push element into newArray
}
}
return newArray; // returns newArray
}
_.reject = function(array, func){
var newArray = []; // initialize newArray
for (var i = 0; i < array.length; i++){ // iterate over array
if (!func(array[i], i, array)){ // test if passing element, index, and array returns not true
newArray.push(array[i]); // if not true, push into newArray
}
}
return newArray; // returns newArray
}
_.partition = function(array, func){
var newArray = [[],[]]; // initialize newArray with two sub arrays
for (var i = 0; i < array.length; i++){ // iterate through array
if (func(array[i], i, array)){ // test if passing element, index, or array is truthy
newArray[0].push(array[i]); // if truthy, push element into newArray[0]
} else { // else, is falsy
newArray[1].push(array[i]); // pushes element into newArray[1]
}
}
return newArray; // returns newArray
}
_.map = function(collection, func){
var newArray = []; // initialize newArray
if (Array.isArray(collection)){ // test if collection is an array
for (var i = 0; i < collection.length; i++){ // if true, iterate through array
newArray.push(func(collection[i], i, collection)); // push the result of passing element, index, or collection into newArray
}
} else { // else, collection is an object
for (var key in collection){ // iterate through collection object
newArray.push(func(collection[key], key, collection)); // push the result of passing value, property or collection into func
}
}
return newArray; // returns newArray
}
_.pluck = function(array, property){
// return f
return array.map(function(value){
return value[property];
});
}
_.every = function(collection, func){
// determine if collection is array
if (Array.isArray(collection)){
//determine if func wasn't passed in
if (func === undefined){
for (var i = 0; i < collection.length; i++){ // iterate
//determine if the current item is not truthy (faster)
if (!collection[i]){
// return false
return false;
}
}
}else {// is array and func was passed
for (let i = 0; i < collection.length; i++){
//determine if current value return false when passed into func
if (func(collection[i], i, collection) === false){
return false;
}
}
}
}else { // it was an object
if (func === undefined){// determine if current value returns false when passed into func
for (var key in collection){//
if (!collection[key]){
return false;
}
}
}else { // func is passed
for (var key in collection){ // iterate through object
if (func(collection[key], key, collection) === false){
return false;
}
}
}
}
return true;
}
_.some = function(collection, func){
if (Array.isArray(collection)){ // test if collection is array
if (func === undefined){ // test if func is not passed
for (var i = 0; i < collection.length; i++){ // loop through collection
if (collection[i]){ // test if at least one item is true
return true; // return true
}
}
}else{ // func is passed
for (var i = 0; i < collection.length; i++){ // iterate through collection
if (func(collection[i], i, collection) === true){ // Test if element is true
return true; // return true
}
}
}
}else { // else collection is an object
if (func === undefined){ // test if func is not passed
for (var key in collection){ // iterate through object
if (func(collection[key], key, collection)){ // Test if element is true
return true; // return true
}
}
}else {
for (var key in collection){
if (func(collection[key], key, collection)){
return true;
}
}
}
}
return false;
}
* _.reduce([1,2,3], function(previousSum, currentValue, currentIndex){ return previousSum + currentValue }, 0) -> 6
*/
//seed value initializes return value
//reult = 0
//iterate through array
// 0
//retult = func(0, 1, 0, [...])
_.reduce = function(array, func, seed){
// create result variable
let result;
// determine if seed did not receive a value
if (seed === undefined){
result = array[0];
for (let i = 1; i < array.length; i++){ // iterate through array at 1 index
result = func(result, array[i], i, array); //
}
} else { // else it did
result = seed;
for (let i = 0; i < array.length; i++){
result = func(result, array[i], i, array);
}
}
return result;
}
_.extend = function(object1, ...moreObjects){
for (var i = 0; i < moreObjects.length; i++){// iterate through moreObjects
Object.assign(object1, moreObjects[i]);// assign current iteration to object1
}
return object1;// return object
}
// return value
return value;
}
_.typeOf = function(value){
if (typeof value === "string"){ // tests if value is a string
return "string"; // returns "string"
} else if (typeof value === "boolean"){ // tests if value is a boolean
return "boolean"; // returns "boolean"
} else if (typeof value === "number"){ // tests if value is a number
return "number"; // returns "number"
} else if (typeof value === "undefined"){ // tests if value is undefined
return "undefined"; // returns "undefined"
} else if (typeof value === "function"){ // tests if value is a function
return "function"; // returns "function"
} else if (value === null){ // tests if value is null
return "null"; // returns "null"
} else{ // any other condition
if (Array.isArray(value)){ // tests if value is an array
return "array"; // returns array
} else { // any other object
return "object"; // returns "object"
}
}
}
_.first = function(arr, num){
if (!Array.isArray(arr) || num < 0){ // tests if arr is not an array
return []; // returns an empty array
} else{ // else, arr is an array
if (num === undefined){ // tests if num is not passed
return arr[0]; // returns first element of array
} else { // else, array is array and num is passed
return arr.slice(0, num);// return the first num elements of the array
}
}
}
_.last = function(arr, num){
if (!Array.isArray(arr) || num < 0){ // tests if arr is an array OR num is negative
return []; // returns empty array
} else { // else, arr is an array
if (num === undefined){ // tests if num is passed
return arr[arr.length - 1]; // if true, returns the last element of the array
} else if (num > arr.length){ // tests if num is greater than the length of array
return arr; // returns whole arr
} else { // else, num is passed
return arr.slice(arr.length - num); // returns the last num elements of the array
}
}
}
_.indexOf = function(arr, val){
for (var i = 0; i < arr.length; i ++){// iterate through arr
if (arr[i] === val){// test if current element is val
return i;// if true, return element index
}
}
return -1; // return -1 in outermost code block
}
_.contains = function(array, value){
// tests if array includes value. Returns true if true, false if false
return (array.includes(value)? true : false);
}
_.each = function(collection, func){
if (Array.isArray(collection)){ // tests if collection is an array
for (var i = 0; i < collection.length; i++){ // iterate through array
func(collection[i], i, collection) // call function for each element, index, and collection
}
} else { // else it's an object
for (var key in collection){ // iterate through object
func(collection[key], key, collection) // call function for each property value, key, collection
}
}
}
_.unique = function(array){
let newArr = []; // initialize newArr array
for (var i = 0; i < array.length; i++){ // iterate through array
if (newArr.indexOf(array[i]) === - 1){ // tests if newArr does not contain current iteration element
newArr.push(array[i]); // push current element into newArr
}
}
return newArr; // returns newArr
}
_.filter = function(array, func){
var newArray = []; // initialize newArray with value of empty of array
for (var i = 0; i < array.length; i++){ // iterate over array
if (func(array[i], i, array)){ // test if passing element, index, and array returns true
newArray.push(array[i]); // if true, push element into newArray
}
}
return newArray; // returns newArray
}
_.reject = function(array, func){
var newArray = []; // initialize newArray
for (var i = 0; i < array.length; i++){ // iterate over array
if (!func(array[i], i, array)){ // test if passing element, index, and array returns not true
newArray.push(array[i]); // if not true, push into newArray
}
}
return newArray; // returns newArray
}
_.partition = function(array, func){
var newArray = [[],[]]; // initialize newArray with two sub arrays
for (var i = 0; i < array.length; i++){ // iterate through array
if (func(array[i], i, array)){ // test if passing element, index, or array is truthy
newArray[0].push(array[i]); // if truthy, push element into newArray[0]
} else { // else, is falsy
newArray[1].push(array[i]); // pushes element into newArray[1]
}
}
return newArray; // returns newArray
}
_.map = function(collection, func){
var newArray = []; // initialize newArray
if (Array.isArray(collection)){ // test if collection is an array
for (var i = 0; i < collection.length; i++){ // if true, iterate through array
newArray.push(func(collection[i], i, collection)); // push the result of passing element, index, or collection into newArray
}
} else { // else, collection is an object
for (var key in collection){ // iterate through collection object
newArray.push(func(collection[key], key, collection)); // push the result of passing value, property or collection into func
}
}
return newArray; // returns newArray
}
_.pluck = function(array, property){
// return f
return array.map(function(value){
return value[property];
});
}
_.every = function(collection, func){
// determine if collection is array
if (Array.isArray(collection)){
//determine if func wasn't passed in
if (func === undefined){
for (var i = 0; i < collection.length; i++){ // iterate
//determine if the current item is not truthy (faster)
if (!collection[i]){
// return false
return false;
}
}
}else {// is array and func was passed
for (let i = 0; i < collection.length; i++){
//determine if current value return false when passed into func
if (func(collection[i], i, collection) === false){
return false;
}
}
}
}else { // it was an object
if (func === undefined){// determine if current value returns false when passed into func
for (var key in collection){//
if (!collection[key]){
return false;
}
}
}else { // func is passed
for (var key in collection){ // iterate through object
if (func(collection[key], key, collection) === false){
return false;
}
}
}
}
return true;
}
_.some = function(collection, func){
if (Array.isArray(collection)){ // test if collection is array
if (func === undefined){ // test if func is not passed
for (var i = 0; i < collection.length; i++){ // loop through collection
if (collection[i]){ // test if at least one item is true
return true; // return true
}
}
}else{ // func is passed
for (var i = 0; i < collection.length; i++){ // iterate through collection
if (func(collection[i], i, collection) === true){ // Test if element is true
return true; // return true
}
}
}
}else { // else collection is an object
if (func === undefined){ // test if func is not passed
for (var key in collection){ // iterate through object
if (func(collection[key], key, collection)){ // Test if element is true
return true; // return true
}
}
}else {
for (var key in collection){
if (func(collection[key], key, collection)){
return true;
}
}
}
}
return false;
}
* _.reduce([1,2,3], function(previousSum, currentValue, currentIndex){ return previousSum + currentValue }, 0) -> 6
*/
//seed value initializes return value
//reult = 0
//iterate through array
// 0
//retult = func(0, 1, 0, [...])
_.reduce = function(array, func, seed){
// create result variable
let result;
// determine if seed did not receive a value
if (seed === undefined){
result = array[0];
for (let i = 1; i < array.length; i++){ // iterate through array at 1 index
result = func(result, array[i], i, array); //
}
} else { // else it did
result = seed;
for (let i = 0; i < array.length; i++){
result = func(result, array[i], i, array);
}
}
return result;
}
_.extend = function(object1, ...moreObjects){
for (var i = 0; i < moreObjects.length; i++){// iterate through moreObjects
Object.assign(object1, moreObjects[i]);// assign current iteration to object1
}
return object1;// return object
}
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