104 lines
3.3 KiB
JavaScript
104 lines
3.3 KiB
JavaScript
/**
|
|
* This program is free software; you can redistribute it and/or
|
|
* modify it under the terms of the GNU General Public License
|
|
* as published by the Free Software Foundation; under version 2
|
|
* of the License (non-upgradable).
|
|
*
|
|
* This program is distributed in the hope that it will be useful,
|
|
* but WITHOUT ANY WARRANTY; without even the implied warranty of
|
|
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
|
|
* GNU General Public License for more details.
|
|
*
|
|
* You should have received a copy of the GNU General Public License
|
|
* along with this program; if not, write to the Free Software
|
|
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
|
|
*
|
|
* Copyright (c) 2015-2021 (original work) Open Assessment Technologies SA ;
|
|
*/
|
|
define(['lodash', 'taoClientDiagnostic/tools/fixedDecimals'], function(_, fixedDecimals) {
|
|
'use strict';
|
|
|
|
/**
|
|
* Gets a getter function that extracts a value from a record.
|
|
* @param {string|Function} name - the name to extract from the record, or a getter function
|
|
* @returns {Function}
|
|
* @private
|
|
*/
|
|
function valueGetter(name) {
|
|
if ('function' === typeof name) {
|
|
return name;
|
|
}
|
|
|
|
return item => (item && item[name]) || 0;
|
|
}
|
|
|
|
/**
|
|
* Computes some stats on a list from a particular field
|
|
* @param {Array|object} list - The list to compute stats on
|
|
* @param {string|Function} fieldName - The name of the field to process, or a callback method returning the value
|
|
* @param {number} [decimals] - Optional number of fixed decimals for values
|
|
* @returns {object}
|
|
*/
|
|
return function stats(list, fieldName, decimals) {
|
|
const getValue = valueGetter(fieldName);
|
|
const values = [];
|
|
let min = Number.MAX_VALUE;
|
|
let max = 0;
|
|
let count = 0;
|
|
|
|
// process first pass stats: compute sum, min and max values
|
|
const sum = _.reduce(
|
|
list,
|
|
(sum, item) => {
|
|
if ('undefined' !== typeof item) {
|
|
const value = getValue(item);
|
|
values.push(value);
|
|
min = Math.min(min, value);
|
|
max = Math.max(max, value);
|
|
sum += value;
|
|
count++;
|
|
return sum;
|
|
}
|
|
},
|
|
0
|
|
);
|
|
|
|
// compute the average value
|
|
const average = sum / (count || 1);
|
|
|
|
// process second pass stats: compute variance
|
|
const sum2 = values.reduce((sum, value) => {
|
|
const diff = value - average;
|
|
sum += diff * diff;
|
|
return sum;
|
|
}, 0);
|
|
|
|
// compute standard variance
|
|
const variance = count > 1 ? Math.sqrt(sum2 / (count - 1)) : 0;
|
|
|
|
// compute the median value
|
|
values.sort();
|
|
const middle = count / 2;
|
|
const median = (values[Math.floor(middle)] + values[Math.ceil(middle)]) / 2;
|
|
|
|
const results = {
|
|
min,
|
|
max,
|
|
sum,
|
|
count,
|
|
average,
|
|
median,
|
|
variance
|
|
};
|
|
|
|
if (decimals) {
|
|
_.forEach(results, (value, key) => {
|
|
results[key] = fixedDecimals(value, decimals);
|
|
});
|
|
}
|
|
|
|
results.values = list;
|
|
return results;
|
|
};
|
|
});
|