Initial commit

.eslintignore

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+coverage/**
+node_modules/**

.eslintrc

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+{
+  "extends": "airbnb/base",
+  "rules": {
+    "strict": 0,
+    "prefer-rest-params": 0
+  }
+}

.gitignore

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+# npm
+node_modules/
+npm-debug.log
+
+# Mocha
+test/mocha.opts
+
+# Coverage
+coverage/

.nvmrc

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+4.6.0

CHANGELOG.md

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+# Changelog
+
+## 1.0.0 (2016-10-06)
+
+* Initial release

LICENSE

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+MIT License
+
+Copyright (c) 2016 SpaceCraft, Inc. (https://gospacecraft.com)
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in all
+copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+SOFTWARE.

README.md

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+# days360
+
+Calculate the difference between two dates based on the [360 day financial year](https://en.wikipedia.org/wiki/360-day_calendar), using the US/NASD method (30US/360) or European method (30E/360). 
+
+Excel's implementation of the US/NASD method has an [incorrect implementation](https://wiki.openoffice.org/wiki/Documentation/How_Tos/Calc:_Date_&_Time_functions#Financial_date_systems). This library provides an Excel compatible US/NASD method.
+
+## Usage
+
+```
+const days360 = require('days360');
+
+days360(new Date('2016-01-01'), new Date('2016-12-31')); // returns 360
+```
+
+### Arguments
+
+* `startDate`: Start date, as a date or milliseconds since Unix epoch
+* `endDate`: End date, as a Date or milliseconds since Unix epoch
+* `method`: An optional argument to specify the calculation
+    * `days360.US` (`0`): calculate using the US/NASD method, with [Excel compatibility](https://wiki.openoffice.org/wiki/Documentation/How_Tos/Calc:_Date_&_Time_functions#Financial_date_systems)
+    * `days360.EU` (`1`): calculate using the European method
+    * `days360.US_NASD` (`2`): calculate using the US/NASD method
+
+## Testing
+
+Tests require [Mocha](http://visionmedia.github.com/mocha) and can be run with `npm test`.  You can specify Mocha options, such as the reporter, by adding a [mocha.opts](http://visionmedia.github.com/mocha/#mocha.opts) file to the `test` directory.
+
+Running `npm test --coverage` will generate code coverage reports with [Istanbul](https://github.com/gotwarlost/istanbul). The code coverage reports will be located in the `coverage` directory, which is excluded from the repository.

circle.yml

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+machine:
+  node:
+    version: 4.6.0
+general:
+  artifacts:
+    - "coverage"
+test:
+  override:
+    - nvm use 4.0.0 && npm test --coverage
+    - nvm use 4.6.0 && npm test --coverage

index.js

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+'use strict';
+
+/**
+ * Imports
+ */
+const isNumber = require('./lib/is-number');
+const isDate = require('./lib/is-date');
+const isLastDay = require('./lib/is-last-day-feb');
+
+/**
+ * Constants
+ */
+const US = 0;
+const EU = 1;
+const US_NASD = 2;
+
+/**
+ * Calculates the nubmer of days between two dates based on a 360-day year, using the US/NASD
+ * method (30US/360) or European method (30E/360).
+ *
+ * Reference:
+ * https://en.wikipedia.org/wiki/360-day_calendar
+ * https://wiki.openoffice.org/wiki/Documentation/How_Tos/Calc:_Date_&_Time_functions#Financial_date_systems
+ *
+ * @param   {Date|Number}     startDate     Start date, as a Date or milliseconds since Unix epoch
+ * @parma   {Date|Number}     endDate       End date, as a Date or milliseconds since Unix epoch
+ * @param   {Boolean|Number}  [method]      0 to calculate using the US/NASD method, with Excel
+ *                                          compatibility (default)
+ *                                          1 to calculate using the European method
+ *                                          2 to calculate using the US/NASD method
+ * @returns {Number}          number of days
+ */
+module.exports = (startDate, endDate, method) => {
+  const start = isNumber(startDate) && startDate >= 0 ? new Date(startDate) : startDate;
+  if (!isDate(start)) {
+    return undefined;
+  }
+  const end = isNumber(endDate) && endDate >= 0 ? new Date(endDate) : endDate;
+  if (!isDate(end)) {
+    return undefined;
+  }
+  let startDay = start.getUTCDate();
+  let endDay = end.getUTCDate();
+  if (method === EU) {
+    // If either date A or B falls on the 31st of the month, that date will be changed to the 30th.
+    startDay = Math.min(startDay, 30);
+    endDay = Math.min(endDay, 30);
+  } else {
+    /**
+     * If both date A and B fall on the last day of February, then date B will be changed to
+     * the 30th (unless preserving Excel compatibility)
+     */
+    const isStartLast = isLastDay(start);
+    if (method === US_NASD && isStartLast && isLastDay(end)) {
+      endDay = 30;
+    }
+    /**
+     * If date A falls on the 31st of a month or last day of February, then date A will be changed
+     * to the 30th.
+     */
+    if (isStartLast || startDay === 31) {
+      startDay = 30;
+    }
+    /**
+     * If date A falls on the 30th of a month after applying (2) above and date B falls on the
+     * 31st of a month, then date B will be changed to the 30th.
+     */
+    if (startDay === 30 && endDay === 31) {
+      endDay = 30;
+    }
+  }
+  return ((end.getUTCFullYear() - start.getUTCFullYear()) * 360)
+    + ((end.getUTCMonth() - start.getUTCMonth()) * 30)
+    + (endDay - startDay);
+};
+
+Object.defineProperties(module.exports, {
+  US_NASD: { value: US_NASD, writable: false, enumerable: true },
+  US: { value: US, writable: false, enumerable: true },
+  EU: { value: EU, writable: false, enumerable: true },
+});

lib/is-date.js

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+'use strict';
+
+/**
+ * Imports
+ */
+const isNumber = require('./is-number');
+
+/**
+ * Constants
+ */
+const TYPE = '[object Date]';
+
+/**
+ * toString reference
+ */
+const toString = Object.prototype.toString;
+
+/**
+ * Check if a value is a valid date
+ *
+ * @param   {Date}      value     Value to validate
+ * @returns {Boolean}   true if a valid date
+ */
+module.exports = (value) => {
+  if (toString.call(value) === TYPE) {
+    return isNumber(value.valueOf());
+  }
+  return false;
+};
+

lib/is-last-day-feb.js

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+'use strict';
+
+/**
+ * Format a date as yyyymd
+ *
+ * @oaram   {Date}    value   Date to format
+ * @returns {String}  formatted date
+ */
+function formatDate(value) {
+  return `${value.getUTCFullYear()}${value.getUTCMonth()}${value.getUTCDate()}`;
+}
+/**
+ * Check if a date is the last day of February
+ *
+ * @param   {Date}      value   Date to validate
+ * @returns {Boolean}   true if the last day of February
+ */
+module.exports = (value) => {
+  if (value.getUTCMonth() === 1) {
+    return formatDate(new Date(value.getUTCFullYear(), 2, 0)) === formatDate(value);
+  }
+  return false;
+};

lib/is-number.js

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+'use strict';
+
+/**
+ * Constants
+ */
+const TYPE = '[object Number]';
+
+/**
+ * toString reference
+ */
+const toString = Object.prototype.toString;
+
+/**
+ * Check if a value is a number and not NaN
+ *
+ * @param   {Number}    value     Value to validate
+ * @returns {Boolean}   true if a valid number
+ */
+module.exports = (value) => {
+  if (toString.call(value) === TYPE && value === +value) {
+    return true;
+  }
+  return false;
+};

package.json

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+{
+  "name": "days360",
+  "version": "1.0.0",
+  "description": "Calculate the difference between two dates based on the 360 day financial year",
+  "keywords": [
+    "days360",
+    "360 day year",
+    "30US/360",
+    "30E/360"
+  ],
+  "author": "SpaceCraft <[email protected]>",
+  "contributors": [
+    "David Wood <[email protected]>"
+  ],
+  "repository": {
+    "type": "git",
+    "url": "git://github.com/spacecraftinc/days360.git"
+  },
+  "bugs": "https://github.com/spacecraftinc/days360/issues",
+  "engines": {
+    "node": ">= 4.0.0"
+  },
+  "main": "./index.js",
+  "dependencies": {},
+  "devDependencies": {
+    "csv": "^1.1.0",
+    "eslint": "^3.6.1",
+    "eslint-config-airbnb": "^12.0.0",
+    "eslint-plugin-import": "^1.16.0",
+    "eslint-plugin-jsx-a11y": "^2.2.2",
+    "eslint-plugin-react": "^6.3.0",
+    "istanbul": "^0.4.5",
+    "mocha": "^3.1.0"
+  },
+  "license": "MIT",
+  "scripts": {
+    "test": "NODE_ENV=test istanbul test _mocha -- --check-leaks --recursive --reporter spec",
+    "lint": "eslint ."
+  }
+}

test/.eslintrc

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+env:
+  mocha: true
+rules:
+  import/no-extraneous-dependencies: [error, { devDependencies: true }]
+  no-plusplus: 0

test/compatibility.js

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+'use strict';
+
+/**
+ * Imports
+ */
+const fs = require('fs');
+const path = require('path');
+const assert = require('assert');
+const csv = require('csv');
+const days360 = require('../');
+
+/**
+ * Constants
+ */
+const DATA_DIR = path.join(__dirname, 'data');
+const READ_OPTIONS = { encoding: 'utf8' };
+const TOTAL = 36 * 36;
+const DATASETS = [
+  { name: 'Google Sheets (EU)', filename: 'google-sheets-eu.csv', method: days360.EU },
+  { name: 'Google Sheets (US/NASD)', filename: 'google-sheets-us.csv', method: days360.US },
+  { name: 'LibreOffice Calc (EU)', filename: 'libreoffice-calc-eu.csv', method: days360.EU },
+  { name: 'LibreOffice Calc (US/NASD)', filename: 'libreoffice-calc-us.csv', method: days360.US },
+  { name: 'Microsoft Excel (EU)', filename: 'microsoft-excel-eu.csv', method: days360.EU },
+  { name: 'Microsoft Excel (US/NASD)', filename: 'microsoft-excel-us.csv', method: days360.US },
+  { name: 'US/NASD (US/NASD)', filename: 'nasd.csv', method: days360.US_NASD },
+  { name: 'OpenOffice Calc (EU)', filename: 'openoffice-calc-eu.csv', method: days360.EU },
+  { name: 'OpenOffice Calc (US/NASD)', filename: 'openoffice-calc-us.csv', method: days360.US },
+];
+
+/**
+ * Read and parse a dataset CSV
+ *
+ * @param   {String}    filename      Filename
+ * @param   {Function}  cb            Callback function
+ */
+function readDataset(filename, cb) {
+  fs.readFile(path.join(DATA_DIR, filename), READ_OPTIONS, (readError, data) => {
+    if (readError) {
+      cb(readError);
+      return;
+    }
+    csv.parse(data, (parseError, rows) => {
+      if (Array.isArray(rows) && rows.length) {
+        cb(null, rows);
+        return;
+      }
+      cb(parseError || new Error('Failed to read dataset'));
+    });
+  });
+}
+
+describe('Compatibility', () => {
+  DATASETS.forEach((dataset) => {
+    it(`should generate the same results as ${dataset.name}`, (done) => {
+      readDataset(dataset.filename, (err, rows) => {
+        assert.strictEqual(err, null);
+        assert.strictEqual(Array.isArray(rows), true);
+        assert.strictEqual(rows.length > 0, true);
+        const columnDates = rows[0].map(value => (value ? new Date(value) : value));
+        const rowDates = rows.map((values) => {
+          const value = values[0];
+          return value ? new Date(value) : value;
+        });
+        let total = 0;
+        columnDates.forEach((columnDate, columnIndex) => {
+          if (columnIndex > 0) {
+            rowDates.forEach((rowDate, rowIndex) => {
+              if (rowIndex > 0) {
+                const result = days360(rowDate, columnDate, dataset.method);
+                const rawValue = rows[rowIndex][columnIndex];
+                const expected = rawValue ? parseInt(rawValue, 10) : 0;
+                assert.strictEqual(result, expected, `Row ${rowIndex} (${rowDate.toISOString()}), Column ${columnIndex} (${columnDate.toISOString()}) does not match`);
+                total += 1;
+              }
+            });
+          }
+        });
+        assert.strictEqual(total, TOTAL);
+        done();
+      });
+    });
+  });
+});

test/data/README.md

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+# Reference Data
+
+The directory contains reference data to validate `days360` calculation compatibility with various office suites. The data consists of a 36x36 matrix, generated from the test vector of dates from [https://bz.apache.org/ooo/show_bug.cgi?id=84934](https://bz.apache.org/ooo/show_bug.cgi?id=84934). This directory also contains the US/NASD dataset from the [days360](https://github.com/tamaloa/days360) gem.
+
+The following office suites were used to generate the data:
+
+* Google Sheets
+* Apple Numbers 4.0
+* Microsoft Excel 15.18
+* LibreOffice Calc 5.5.2
+* OpenOffice Calc 4.1.2
+
+Microsoft Excel and Apple Numbers both offer desktop and web-based versions. It was verified that both versions generate the same data.