# vizier.js
Fetch data tables from VizieR in the browser
[](https://badge.fury.io/js/%40jobovy%2Fvizier)
[](https://www.jsdelivr.com/package/npm/@jobovy/vizier)
[](https://codecov.io/gh/jobovy/vizier.js)
## Overview
This small javascript package allows you to fetch a table from [VizieR](https://vizier.u-strasbg.fr/) asynchronously and process the data table into a dictionary according to the ReadMe.
## Author
Jo Bovy (University of Toronto): bovy - at - astro - dot - utoronto - dot - ca
## Usage
Only very basic usage is currently implemented. See [examples/basic.html](examples/basic.html) for a fully worked basic example. An example of loading a single file that contains both the ReadMe and the data and that is *not* on the CDS servers is given in [examples/onefile.html](examples/onefile.html).
Load the library, e.g., from jsDelivr using
```
```
for the latest version or specify the version with (update 1.0.2 to later versions as necessary)
```
```
This exposes a global variable ``VizieR`` that contains the functionality of this package.
Fetch a table by specifying the catalog's name (e.g., 'J/A+A/545/A32'), the specific table within the catalog's name (e.g., 'table4.dat'), and the name of the ReadMe (optional, e.g., 'ReadMe'). This returns a Promise that returns the data dictionary and the header, which you can then process with a ``then`` function. For example,
```
VizieR.fetch('J/A+A/545/A32','table4.dat','ReadMe')
.then(function (dataAndHeader) {
let [data,header]= dataAndHeader;
// do stuff with the data and/or the header!
});
```
You can also fetch a table from a general URL, in that case just set the first argument to ``null``. For example,
```
VizieR.fetch(null,'https://raw.githubusercontent.com/jobovy/sparc-rotation-curves/main/data/MassModels_Lelli2016c.mrt')
.then(function (dataAndHeader) {
let [data,header]= dataAndHeader;
// do stuff with the data and/or the header!
});
```
## Publishing a new version of this package
Follow the following steps:
* Update the version in ``package.json`` and then run ``npm install``. Commit updated version in ``package.json`` and ``package-lock.json``
* Create a new git tag for this version: ``git tag vX.X.X``
* Package up for npm: ``npm pack``, check that no extraneous files are included
* Publish to npm: ``npm publish --access public``
* Done!