hed-validator

This package contains a JavaScript validator for HED (Hierarchical Event Descriptor) annotations for tabular files and their associated JSON metadata files such as those found in datasets formatted in BIDS (Brain Imaging Data Structure).

HED is a system for annotating events using comma-separated path strings. Any type of event can be annotated using HED-type syntax. The HED annotation strategy is very general and a standardized vocabulary in the form of a HED schema enables annotation of events in an understandable, machine-actionable format.

The current focus of the hed-validator package is to support full validation of HED in BIDS datasets under the BIDS validator 2.0. A sample of current hed-validator usage in BIDS can be found in the BIDS validator in hed.ts.

Online validation

A browser-based validator that uses this package is available at www.hedtags.org/hed-javascript. This online validator allows users to validate HED annotations in a web browser without needing to install any software or upload files to a server. The API documentation for this package is available at www.hedtags.org/hed-javascript/docs.

A number of tools for HED, including validation are also available in a Python-based online validator.

All source code for these tools as well as the HED specification and other resources are available on the GitHub hed-standard organization. The HED project homepage is www.hedtags.org.

Usage in node environment

The hed-validator package can be used in a Node.js environment to validate HED annotations. You must install the npm hed-validator package and add: require('hed-validator').

// In a Node.js environment:
const { BidsDataset, BidsDirectoryAccessor } = require('hed-validator')
const path = require('path')

async function main() {
  const dataRoot = path.join(__dirname, 'path/to/bids/dataset')
  const [dataset, issues] = await BidsDataset.create(dataRoot, BidsDirectoryAccessor)
  if (dataset) {
    const validationIssues = await dataset.validate()
    // process issues
  } else {
    // process creation issues
  }
}

main()

Repository notes

The main branch is now the default branch. All changes to the repository should be done as PRs (pull requests) to the main branch.

Running the browser locally

cd browser
npm install
npm run build
npm run preview