web-annotation-utils

web-annotation-utils

TypeScript types and utility functions for handling Web Annotations.

A Web Annotation, as defined by the Web Annotation Data Model is basically a JSON object with a target (what the note is ‘about’) and a body (the note ‘content’); along with optional metadata (creator, date, motivation, etc.). This module provides a TypeScript type declaration for Web Annotations.

Besides the type definition, it provides convenience functions for dealing with Web Annotations, such as getting the URL(s) of pages an annotation targets, or the plain text content the annotation body. It aims to provide some basic tools to get started writing interoperable annotation tools without having to deal with the intricacies of the data model.

Usage

Install, using npm or equivalent:

npm install git+https://code.treora.com/gerben/web-annotation-utils#latest

Usage example:

import type { WebAnnotation } from 'web-annotation-utils';
import { completeAnnotationStub, getTargetUrls } from 'web-annotation-utils';

const webAnnotation: WebAnnotation = completeAnnotationStub({
  "bodyValue": "interesting.",
  "target": [
    "http://example.org/page1",
    {
      "source": "http://example.org/page2",
      "selector": {
        "type": "TextQuoteSelector",
        "exact": "bla bla bla",
      }
    }
  ]
});

const targetUrls = getTargetUrls(webAnnotation.target);
// [ 'http://example.org/page1', 'http://example.org/page2' ]

Types

See WebAnnotation.ts.

:toolbox: Functions

• asArray
• asSingleValue
• findTargetsInDocument
• findTargetInDocument
• completeAnnotationStub
• getSingleCreatorName
• targetsUrl
• getTargetUrls
• getTargetUrl
• getTargetQuotes
• getTargetQuote

:gear: asArray

Function	Type
asArray	<T>(value: ZeroOrMore<T>) => T[]

:gear: asSingleValue

Function	Type
asSingleValue	<T>(value: ZeroOrMore<T>) => T

:gear: findTargetsInDocument

Find the Elements and/or Ranges in the document the annotation targets, if any.

This supports the following selector types:

• CssSelector
• TextQuoteSelector
• TextPositionSelector
• RangeSelector

Function	Type
findTargetsInDocument	(target: OneOrMore<Target>, document?: Document) => Promise<DomMatch[]>

:gear: findTargetInDocument

Find the Elements and/or Ranges in the document the annotation targets, if any, given a single target.

This supports the following selector types:

• CssSelector
• TextQuoteSelector
• TextPositionSelector
• RangeSelector

Function	Type
findTargetInDocument	(target: Target, document?: Document) => Promise<DomMatch[]>

:gear: completeAnnotationStub

Turn a partial annotation into a ‘well-formed’ WebAnnotation.

It sets the following properties, if absent in the given stub:

• @context as required
• type as required, to 'Annotation'
• created as recommended (to the current time)
• target to 'about:invalid'

Function	Type
completeAnnotationStub	(annotationStub: Partial<WebAnnotation>) => WebAnnotation

:gear: getSingleCreatorName

Get the name of the creator. If there are multiple, returns the first. Assumes the creator is a nested Agent object: if the creator a string (presumably the URL of an Agent node), undefined is returned.

Function	Type
getSingleCreatorName	(annotationOrBody: WebAnnotation or BodyObject) => string

:gear: targetsUrl

Check whether the annotation likely targets the given URL.

The word “likely” is used because, in its comparison, this ignores the URL scheme, fragment and query parameters.

Note that, strictly speaking, a URL should be treated as an opaque string. In practice, it may however be useful to consider URLs as ‘likely equivalent’ in order to apply annotations targeting one URL to the document with the very similar URL. Apply with caution: Especially a different query may, depending on the website at hand, result in very different documents.

Function	Type
targetsUrl	(target: OneOrMore<Target>, url: string) => boolean

:gear: getTargetUrls

Get the URLs of the resources that the annotation targets, for all its targets.

Function	Type
getTargetUrls	(target: OneOrMore<Target>) => string[]

:gear: getTargetUrl

Get the URL of the resource that the annotation targets, for a single target.

Function	Type
getTargetUrl	(target: Target) => string

:gear: getTargetQuotes

Get the exact quotes that the annotation targets using a TextQuoteSelector, if any.

Function	Type
getTargetQuotes	(target: OneOrMore<Target>) => string[]

:gear: getTargetQuote

Get the exact quote that a single target of an annotation targets using a TextQuoteSelector, if any.

Function	Type
getTargetQuote	(target: Target) => string

Licence

This is free and unencumbered software released into the public domain.