UnderScore.JS Tutorial [ARRAY FUNCTION EXAMPLES]

/**

 * Author Piyush Arya

* Email : arya.piyush87@gmail.com

 * Module :- UnderScore.js Tutorial

 * Date Created :- Jan 2014

 */

var contactList = {

"returnList" : [{

"name" : "NAME",

"password" : "dummy",

"time" : "today",

"email" : "a.com"

}],

};

window.logger = function(param) {

return console.log(param);

};

var arr = ["1", "2", "3", "4", "5"], every = [true, 0, "hello"], invokeSort = [[3, 6, 5, 2, 4, 1], ["b", "d", "c", "a"]], invokeupper = ["b", "d", "c", "a"], arrColl = [1, 2, 3, 4, 5], json = [{

"name" : "piyush",

"email" : "demo@gmail.com",

"age" : 25

}, {

"name" : "piyush",

"email" : "demo@yahoo.com",

"age" : 26

}, {

"name" : "arya",

"email" : "demo@hotmail.com",

"age" : 27

}];

/* ************* ARRAY FUNCTION EXAMPLES ********************  */


/* ****  UNCOMMENT LOGGER TO SEE THE RESULT IN CONSOLE*****  */


/* ------------------first Function Starts------------------------------------ */

var firstDemo = _.first(arrColl);
//var firstDemo = _.first(arrColl,3);
// 1 2 3 when passed 3 as parameter
//logger("firstDemo --> " + firstDemo);
// Returns the first element of an array

/* -----------------------first Function end--------------------------- */


/* -----------------------initial Function Starts------------------------ */

var initialDemo = _.initial(arrColl);
//var initialDemo = _.first(arrColl,2);
// 1 2 when pass 2 as parameter
//logger("initialDemo --> " + initialDemo);
// Returns everything but the last entry of the array

/* -------------------------initial Function end------------------------- */


/* -------------------------last Function Starts------------------------ */

var lastDemo = _.last(arrColl);
//var lastDemo = _.last(arrColl,3);
// 3 4 5 when pass 3 as parameter
//logger("lastDemo --> " + lastDemo);
// Returns the last element of an array

/* --------------------------last Function end------------------------ */


/* --------------------------rest Function Starts------------------------ */

//var restDemo = _.rest(arrColl);
var restDemo = _.rest(arrColl, 3);
// 4 5 when pass 3 as parameter
//logger("restDemo --> " + restDemo);
// Returns the rest of the elements in an array

/* ---------------------------rest Function end------------------------------- */


/* ---------------------------compact Function Starts----------------------- */

var compactDemo = _.compact([0, 1, false, 2, '', 3, null, undefined, '1', '2', 4]);
//logger("compactDemo --> " + compactDemo);
// Returns a copy of the array with all falsy values removed

/* -----------------------compact Function end------------------------------ */


/* ----------------------flatten Function Starts------------------------------- */

var flattenDemo = _.flatten([1, [2], [3, [[4]]]], true);
//logger("flattenDemo --> " + flattenDemo);
// Flattens a nested array (the nesting can be to any depth).

/* -----------------------flatten Function end------------------------------- */


/* ----------------------without Function Starts------------------------- */

var withoutDemo = _.without([1, 2, 1, 0, 3, 1, 4], 0, 1);
//logger("withoutDemo --> " + withoutDemo);
// Returns a copy of the array with all instances of the values removed.

/* ------------------------without Function end------------------------------- */



/* -------------------------union Function Starts------------------------------- */

var unionDemo = _.union([1, 2, 3], [101, 2, 1, 10], [2, 1, 9]);
//logger("unionDemo --> " + unionDemo);
// Computes the union of the passed-in arrays: the list of unique items.

/* -------------------------union Function end---------------------------------- */


/* ------------------------intersection Function Starts--------------------------- */

var intersectionDemo = _.intersection([1, 2, 3], [101, 2, 1, 10], [2, 1]);
//logger("intersectionDemo --> " + intersectionDemo);
// Computes the list of values that are the intersection of all the arrays

/* --------------------------intersection Function end---------------------------- */

/* -------------------------difference Function Starts---------------------------- */

var differenceDemo = _.difference([1, 2, 3, 4, 5], [5, 2, 10]);
//logger("differenceDemo --> " + differenceDemo);
// Similar to without, but returns the values from array that are not present in the other arrays.

/* -----------------------difference Function end--------------------------------- */


/* ----------------------uniq Function Starts--------------------------------------- */

var uniqDemo = _.uniq([1, 2, 1, 4, 1, 3]);
//Produces a duplicate-free version of the array, using === to test object equality.
//logger("uniqDemo --> " + uniqDemo);

/* ---------------------uniq Function end--------------------------------------------- */

/* ----------------------zip Function Starts-------------------------------------------- */

var zipDemo = _.zip(['moe', 'larry', 'curly'], [30, 40, 50], [true, false, false]);
//Merges together the values of each of the arrays with the values at the corresponding position.
//logger("zipDemo --> " + zipDemo);

/* ------------------------zip Function end-------------------------------------------- */

/* ------------------------object Function Starts-------------------------------------- */

var objectDemo = _.object(['moe', 'larry', 'curly'], [30, 40, 50]);
//var objectDemo = _.object([['moe', 30], ['larry', 40], ['curly', 50]]);
//Converts arrays into objects. If duplicate keys exist, the last value wins.
//logger("objectDemo --> " + JSON.stringify(objectDemo));

/* -------------------------object Function end---------------------------------------- */


/* ------------------------- -indexOfDemo Function Starts-------------------------- */
var indexOfDemo = _.indexOf([1, 2, 3], 2);
//Returns the index at which value can be found in the array, or -1 if value is not present in the array
// Starts with 0
//logger("indexOfDemo --> " + indexOfDemo);

/* ---------------------------indexOfDemo Function end----------------------------- */


/* --------------------------lastIndexOfDemo Function Starts------------------------- */

var lastIndexOfDemo = _.lastIndexOf([1, 2, 3, 1, 2, 3], 2);
// starts with 0
//Returns the index of the last occurrence of value in the array, or -1 if value is not present.
//logger("lastIndexOfDemo --> " + lastIndexOfDemo);

/* --------------------------lastIndexOfDemo Function end----------------------------- */


/* -------------------------sortedIndex Function Starts---------------------------------- */

var sortedIndexDemo = _.sortedIndex([10, 20, 30, 40, 50], 55);
// starts with 0
//Uses a binary search to determine the index at which the value should be inserted into the list in order to //maintain the list's sorted order
//logger("sortedIndexDemo --> " + sortedIndexDemo);

/* --------------------------sortedIndex Function end------------------------------------ */

/* ---------------------------range Function Starts---------------------------------------- */

var rangeDemo = _.range(10);
//var rangeDemo = _.range(1, 11);
//var rangeDemo =_.range(0, 30, 5);
//var rangeDemo =_.range(0, -10, -1);
//var rangeDemo =_.range(0);
//logger("rangeDemo --> " + rangeDemo);

/* --------------------------range Function end------------------------------------------ */

Click Here For Underscore Collections Functions with Examples

Click Here For Underscore Functions with Examples