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.

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.

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.

// 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()

Usage from JavaScript

The JavaScript version of the HED validator, implemented in this package, is meant primarily to be called during validation of BIDS datasets and is called by the bids-validator. This package has been deployed on npm as hed-validator.

To use the hed-validator, you must install the npm hed-validator package and add: import hedValidator from 'hed-validator' to your JavaScript program.

A sample of current hed-validator usage can be found in the BIDS validator in hed.ts.

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.