Helpers

applesauce-core and other packages export helper methods for working with events.

WARNING

Some helper methods may throw errors. make sure your app can handle errors correctly.

Core helpers

The applesauce-core package contains the majority of the helper methods

Events

• isEvent Checks if an object is a nostr event
• markFromCache Marks an event as being from the cache
• isFromCache Checks if an event is marked from cache
• getTagValue Gets the value of the first tag matching the name
• getIndexableTags Get a Set of all indexable tags on the event

Event relays

• addSeenRelay Adds a relay to the list of relay the event was seen on
• getSeenRelays Get the list of relays this event was seen on

Pointers

• getEventPointerFromETag Creates an EventPointer from a standard "e" tag
• getEventPointerFromQTag Creates an EventPointer from a standard "q" tag
• getAddressPointerFromATag Creates an AddressPointer from a standard "a" tag
• getProfilePointerFromPTag Creates an ProfilePointer from a standard "p" tag
• getAddressPointerForEvent Returns an AddressPointer for a replaceable event

Delete events

• getDeleteEventPointers Gets a list of referenced event ids
• getDeleteAddressPointers Get the list of replaceable event coordinates the event is referencing

URLs

• getURLFilename returns the filename part fo the path in a URL
• isAudioURL Checks if the URL ends with a audio file extension
• isVideoURL Checks if the URL ends with a video file extension
• isImageURL Checks if the URL ends with a image file extension
• isStreamURL Checks if the URL ends with a stream file extension

Tags

• isETag Checks if tag is an "e" tag and has at least one value
• isATag Checks if tag is an "a" tag and has at least one value
• isPTag Checks if tag is an "p" tag and has at least one value
• isDTag Checks if tag is an "d" tag and has at least one value
• isRTag Checks if tag is an "r" tag and has at least one value
• isTTag Checks if tag is an "t" tag and has at least one value

Hidden Tags

Hidden tags are used in NIP-51 lists and NIP-60 wallets

• canHaveHiddenTags Checks if a given event kind can have hidden tags
• hasHiddenTags Checks if an event has hidden tags
• getHiddenTags Returns the hidden tags for an event if they are unlocked
• isHiddenTagsUnlocked Checks if the hidden tags are locked
• unlockHiddenTags Unlocks the hidden tags using a signer

Filters

• isFilterEqual Check if two filters are equal

Time

• unixNow Returns the current unix timestamp

Feature helpers

Helpers for specific event kinds live in applesauce-common (and a few in applesauce-core) and are documented on the feature pages that use them, such as Profiles, Mailboxes & Outbox, Comments, and Zaps. Emoji helpers are covered in Content.

Factory Helpers

The applesauce-core package exports some helpers for building events and tags

Some of the most useful ones are

• fillAndTrimTag Replaces undefined or null in tags with "" and trims to tag down to a set length if it ends with ""
• createQTagFromEventPointer Creates a "q" tag for from an EventPointer to tag quoted events
• createPTagFromProfilePointer Creates a "p" tag for from a ProfilePointer to tag mentioned pubkeys