initial commit

.gitignore

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+node_modules/
+dist/
+.env

CHANGELOG.md

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+# Changelog
+
+All notable changes to this project will be documented in this file.
+
+## [1.0.0] - 2023-11-11
+
+- Initial release

LICENSE

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+ISC License
+
+Copyright (c) 2023, [Your Full Name]
+
+Permission to use, copy, modify, and/or distribute this software for any purpose with or without fee is hereby granted, provided that the above copyright notice and this permission notice appear in all copies.
+
+THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.

README.md

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+# nrel-spa
+
+NREL SPA (Solar Position Algorithm) native implementation in JavaScript. This package allows for precise calculations of solar positions and phases based on geographical coordinates and time.
+
+## Installation
+
+```bash
+npm install nrel-spa
+```
+
+## Usage
+
+Basic usage examples:
+
+```javascript
+const { calcSpa } = require('nrel-spa');
+
+const myLat = 40.7128; // Latitude for New York City
+const myLng = -74.006; // Longitude for New York City
+const myDate = new Date(); // Current date
+
+const solarData = calcSpa(myDate, myLat, myLng);
+console.log(solarData);
+```
+
+## API
+
+Describe the functions and their parameters briefly.
+
+## Contributing
+
+Contributions are welcome! Please read our [contributing guidelines](CONTRIBUTING.md).
+
+## License
+
+This project is licensed under the ISC License - see the [LICENSE](LICENSE) file for details.

index.js

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+const spa = require('./dist/spa');
+
+function fractalTime(fractionalHour) {
+    const hours = Math.floor(fractionalHour);
+    const minutes = Math.floor((fractionalHour - hours) * 60);
+    const seconds = Math.floor((fractionalHour * 3600) - (hours * 3600) - (minutes * 60));
+    const ms = Math.floor((fractionalHour * 3600000) - (hours * 3600000) - (minutes * 60000) - (seconds * 1000));
+    return `${hours.toString().padStart(2, '0')}:${minutes.toString().padStart(2, '0')}:${seconds.toString().padStart(2, '0')}.${ms.toString().padStart(3, '0')}`;
+}
+
+function adjustForCustomAngle(baseSpaData, zenithAngle) {
+    let adjustedData = { ...baseSpaData };
+    const standardZenith = 90.83;
+    const angleDifference = zenithAngle - standardZenith;
+    const timeAdjustment = angleDifference / 360 * 24;
+    adjustedData.sunrise -= timeAdjustment;
+    adjustedData.sunset += timeAdjustment;
+    return adjustedData;
+}
+
+function getSpa(date, lat, lng, params = null, angles = []) {
+    let data = new spa.SpaData();
+    data.year = date.getFullYear();
+    data.month = date.getMonth() + 1; // JavaScript months are 0-indexed
+    data.day = date.getDate();
+    data.hour = date.getHours();
+    data.minute = date.getMinutes();
+    data.second = date.getSeconds();
+    data.longitude = lng;
+    data.latitude = lat;
+
+    // Set default values if optional parameters are not provided
+    data.elevation = params?.elevation ?? 10;
+    data.pressure = params?.pressure ?? 1013.25;
+    data.temperature = params?.temperature ?? 15;
+    data.timezone = params?.timezone ?? -5;
+    data.function = spa.SPA_ALL;
+
+
+    let result = spa.spa_calculate(data);
+    let output = {};
+
+    if (result === 0) {
+        output = {
+            zenith: data.zenith,
+            azimuth: data.azimuth,
+            sunrise: data.sunrise,
+            solarNoon: data.suntransit,
+            sunset: data.sunset
+        };
+
+        if (angles.length > 0) {
+            output.angles = angles.map(angle => {
+                let customSpaData = adjustForCustomAngle({ ...data }, angle);
+                return {
+                    sunrise: customSpaData.sunrise,
+                    sunset: customSpaData.sunset
+                };
+            });
+        }
+    } else {
+        console.error('SPA Calculation failed');
+    }
+
+    return output;
+}
+
+function calcSpa(date, lat, lng, params = null, angles = []) {
+    let rawData = getSpa(date, lat, lng, params, angles);
+    rawData.sunrise = fractalTime(rawData.sunrise);
+    rawData.solarNoon = fractalTime(rawData.solarNoon);
+    rawData.sunset = fractalTime(rawData.sunset);
+
+    if (rawData.angles) {
+        rawData.angles = rawData.angles.map(angleData => {
+            return {
+                sunrise: fractalTime(angleData.sunrise),
+                sunset: fractalTime(angleData.sunset)
+            };
+        });
+    }
+
+    return rawData;
+}
+
+module.exports = {
+    getSpa,
+    calcSpa,
+    fractalTime
+};

package.json

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+{
+  "name": "nrel-spa",
+  "version": "1.0.0",
+  "description": "NREL SPA native implementation in JS",
+  "main": "index.js",
+  "scripts": {
+    "test": "node test.js"
+  },
+  "repository": {
+    "type": "git",
+    "url": "git+https://github.com/ussunnah/nrel-spa.git"
+  },
+  "keywords": [
+    "spa",
+    "nrel",
+    "solar",
+    "calculator"
+  ],
+  "author": "USF",
+  "license": "ISC",
+  "bugs": {
+    "url": "https://github.com/ussunnah/nrel-spa/issues"
+  },
+  "homepage": "https://github.com/ussunnah/nrel-spa#readme",
+  "devDependencies": {
+  }
+}

test.js

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+const { getSpa, calcSpa } = require('./index');
+
+// Constants for testing
+const myLat = 40.7128; // Latitude for New York City
+const myLng = -74.006; // Longitude for New York City
+const nyDate = new Date(new Date().toLocaleString("en-US", { timeZone: "America/New_York" }));
+const myDate = new Date(); // Date object for today with NY time zone
+const myAngles = [63.435]; // Custom angles for twilight calculations
+
+// Get results
+const get = getSpa(myDate, myLat, myLng, null, myAngles);
+const calc = calcSpa(myDate, myLat, myLng, null, myAngles);
+
+// Print results
+console.log("\nTest: Using NYC and current time:\n")
+console.log("getSpa =", JSON.stringify(get, null, 2), "\n");
+console.log("calcSpa =", JSON.stringify(calc, null, 2), "\n");