latlon-formatter

A set of functions to format latitude and longitude angles.

Installation

npm install latlon-formatter --save

Usage

• ES6:

```javascript
import { formatLatitude, formatLongitude } from 'latlon-formatter';
const latitude = formatLatitude(Math.PI / 3); // => 60° 00′ 00″ N 
const longitude = formatLongitude(-33.4, {
    degrees: true
});   // => 034° 24′ 00″ W 
```

• require with Node.js:

```javascript
var formatter = require('latlon-formatter');
var latitude = formatter.latitude(Math.PI / 3); // => 60° 00′ 00″ N 
var longitude = formatter.longitude(-33.4, {
    degrees: true
});   // => 034° 24′ 00″ W
```

• in browser include dist/latlon-formatter.js or dist/latlon-formatter.min.js script:

```javascript
var formatter = window.latlonFormatter;
var latitude = formatter.latitude(Math.PI / 3); // => 60° 00′ 00″ N 
var longitude = formatter.longitude(-33.4, {
    degrees: true
});   // => 034° 24′ 00″ W
```

Methods

• latitude or formatLatitude — format latitude angle.

Arguments:

- `value` — angle's value;
- `options`:
    - `template` — custom template (optional, default — `{degree}° {prime}′ {doublePrime}″ {direction}`);
    - `degrees` — specifies whether `value` is in degrees or in radians (optional, default — `false`);
    - `fixedCount` — count of precision digits (optional, default — `null` leaving precision as is).

Examples:

```javascript
formatter.latitude(33.4); // => 34° 24′ 00″ N
```

```javascript
formatter.latitude(-14.75, { degrees: true }); // => 14° 45′ 00″ S
```

```javascript
formatter.latitude(-14.75, {
    template: '{negativeSign}{value}°',
    degrees: true,
    fixedCount: 1
}); // => —14.8°
```

• longitude or formatLongitude — format longitude angle.

Arguments:

- `value` — angle's value;
- `options`:
    - `template` — custom template (optional, default — `{degree}° {prime}′ {doublePrime}″ {direction}`);
    - `degrees` — specifies whether `value` is in degrees or in radians (optional, default — `false`);
    - `fixedCount` — count of precision digits (optional, default — `null` leaving precision as is).

Examples:

```javascript
formatter.longitude(33.4); // => 034° 24′ 00″ E
```

```javascript
formatter.longitude(-14.75, { degrees: true }); // => 014° 45′ 00″ W
```

```javascript
formatter.longitude(-14.75, {
    template: '{negativeSign}{value}°',
    degrees: true,
    fixedCount: 1
}); // => —14.8°
```

• angle or formatAngle — format any custom angle.

Arguments:

- `value` — angle's value;
- `options`:
    - `template` — custom template (optional, default — `{negativeSign}{value}°`);
    - `degrees` — specifies whether `value` is in degrees or in radians (optional, default — `false`);
    - `fixedCount` — count of precision digits (optional, default — `null` leaving precision as is);
    - `customTokens` — an object or a function returning an object of additional custom tokens used in `template`.
     
Examples:

```javascript
formatter.angle(3.4, {
    template: '{degree}° {prime}′ {doublePrime}″ {direction}',
    customTokens: f => {
        return {
            degree: (f.degrees < 10 ? '0' : '') + f.degree,
            direction: f.sign >= 0 ? 'N' : 'S'
        };
    }
}); // => 03° 24′ 00″ N
```
    

Template tokens

All three format methods (latitude, longitude and angle) have the following predefined template tokens:

• value — angle's absolute value with optional precision specified by fixedCount option;
• degree — absolute (two-digits and three-digits for latitude and longitude respectively) degree value;
• prime — absolute two-digits prime value;
• doublePrime — absolute two-digits double prime value;
• sign — value's sign:

- `+` — positive value;
- `—` — negative value;
- empty — zero value;

• negativeSign — the same as sign except that it's empty for both zero and positive values.

latitude and longitude methods additionally have direction token:

• N — non-negative latitude;
• S — negative latitude;
• E — non-negative longitude;
• W — negative longitude.

Any custom additional tokens can be specified by customTokens option of angle method.

Building

In order to build library run:

    npm run build
    

Testing

Run unit tests:

npm test

Run tests with coverage:

npm run test:coverage

In order to run tests with Coveralls locally you have to provide COVERALLS_REPO_TOKEN:

    COVERALLS_REPO_TOKEN=<token> npm run test:coveralls
    

Contributing

Before making a pull request, please, be sure that you start from develop branch.

License

MIT