Tested using the main branch from loraine lab. Used the same testing strategy outlined in my previous comment.

Files loaded in IGB appeared identical and matched with the REST call.

Closing ticket.

New PR is merged. New "early access" installers are built and deployed to BioViz.org.

Merged.

Raised a Pull Request: https://bitbucket.org/lorainelab/integrated-genome-browser/pull-requests/993. Please review and let me know if there are any issues.

Tested using file downloaded from UCSC table browser (encTfChipPkENCFF635MUK.narrowPeak) and comparing to the same file as loaded through UCSC REST API (encTfChipPkENCFF635MUK).
Also compared to the following REST call: https://api.genome.ucsc.edu/getData/track?genome=hg38&track=encTfChipPkENCFF635MUK&chrom=chr1&start=1615401&end=1616106

Files loaded in IGB appeared identical and matched with the REST call.

Ready for pull request.

Code changes are completed to include the narrowPeak file type as well in the supported file types for UCSC and added logic to parse them. Written test case for the same. Updated code is available at the branch: https://bitbucket.org/jaya-sravani/integrated-genome-browser/branch/IGBF-3657.
To test:

1. Download https://bitbucket.org/jaya-sravani/integrated-genome-browser/downloads/ installer or clone this branch to local https://bitbucket.org/jaya-sravani/integrated-genome-browser/branch/IGBF-3657 and start the application.
2. Select a particular genome. (note: hg38 has data for this track)
3. Select any narrowPeak track (dataset) type.
4. Click on the load data button either from the top right corner or in the data management table.
5. Check whether the data is loaded correctly and the peak is visible.

Use logic in the parseLineToDataModel method in NarrowPeak Symloader class to create parsing logic for narrowPeak file type in the UCSC Rest API module.