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| import $ from 'jquery';
import func from './func';
/**
* returns the first item of an array.
*
* @param {Array} array
*/
function head(array) {
return array[0];
}
/**
* returns the last item of an array.
*
* @param {Array} array
*/
function last(array) {
return array[array.length - 1];
}
/**
* returns everything but the last entry of the array.
*
* @param {Array} array
*/
function initial(array) {
return array.slice(0, array.length - 1);
}
/**
* returns the rest of the items in an array.
*
* @param {Array} array
*/
function tail(array) {
return array.slice(1);
}
/**
* returns item of array
*/
function find(array, pred) {
for (let idx = 0, len = array.length; idx < len; idx++) {
const item = array[idx];
if (pred(item)) {
return item;
}
}
}
/**
* returns true if all of the values in the array pass the predicate truth test.
*/
function all(array, pred) {
for (let idx = 0, len = array.length; idx < len; idx++) {
if (!pred(array[idx])) {
return false;
}
}
return true;
}
/**
* returns index of item
*/
function indexOf(array, item) {
return $.inArray(item, array);
}
/**
* returns true if the value is present in the list.
*/
function contains(array, item) {
return indexOf(array, item) !== -1;
}
/**
* get sum from a list
*
* @param {Array} array - array
* @param {Function} fn - iterator
*/
function sum(array, fn) {
fn = fn || func.self;
return array.reduce(function(memo, v) {
return memo + fn(v);
}, 0);
}
/**
* returns a copy of the collection with array type.
* @param {Collection} collection - collection eg) node.childNodes, ...
*/
function from(collection) {
const result = [];
const length = collection.length;
let idx = -1;
while (++idx < length) {
result[idx] = collection[idx];
}
return result;
}
/**
* returns whether list is empty or not
*/
function isEmpty(array) {
return !array || !array.length;
}
/**
* cluster elements by predicate function.
*
* @param {Array} array - array
* @param {Function} fn - predicate function for cluster rule
* @param {Array[]}
*/
function clusterBy(array, fn) {
Iif (!array.length) { return []; }
const aTail = tail(array);
return aTail.reduce(function(memo, v) {
const aLast = last(memo);
if (fn(last(aLast), v)) {
aLast[aLast.length] = v;
} else {
memo[memo.length] = [v];
}
return memo;
}, [[head(array)]]);
}
/**
* returns a copy of the array with all false values removed
*
* @param {Array} array - array
* @param {Function} fn - predicate function for cluster rule
*/
function compact(array) {
const aResult = [];
for (let idx = 0, len = array.length; idx < len; idx++) {
if (array[idx]) { aResult.push(array[idx]); }
}
return aResult;
}
/**
* produces a duplicate-free version of the array
*
* @param {Array} array
*/
function unique(array) {
const results = [];
for (let idx = 0, len = array.length; idx < len; idx++) {
if (!contains(results, array[idx])) {
results.push(array[idx]);
}
}
return results;
}
/**
* returns next item.
* @param {Array} array
*/
function next(array, item) {
const idx = indexOf(array, item);
if (idx === -1) { return null; }
return array[idx + 1];
}
/**
* returns prev item.
* @param {Array} array
*/
function prev(array, item) {
const idx = indexOf(array, item);
if (idx === -1) { return null; }
return array[idx - 1];
}
/**
* @class core.list
*
* list utils
*
* @singleton
* @alternateClassName list
*/
export default {
head,
last,
initial,
tail,
prev,
next,
find,
contains,
all,
sum,
from,
isEmpty,
clusterBy,
compact,
unique
};
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