The cool thing about it is that plain text inputs generate plain text deltas (binary inputs, of course, may generate binary deltas).
$ npm install fossil-delta
import { createDelta, applyDelta } from 'fossil-delta';
Returns a delta from source to target.
source
and target
must be a Uint8Array
or an Array
of bytes.
The same type will be returned.
Returns the target by applying the delta to the origin.
origin
and delta
must be a Uint8Array
or an Array
of bytes.
The same type will be returned.
Throws an error if the delta fails to apply (e.g., if it is corrupted).
Optional argument opts
can be:
{
verifyChecksum: false
}
to disable checksum verification (which is enabled by default.)
Returns the size of the target for this delta.
Throws an error if it cannot read the size from the delta.
A nice property of the Fossil Delta Encoding is that it produces pure plain text deltas if the source and target are plain text.
To simplify working with plain text strings, the library provides the following convenience functions,
which automatically encode and decode strings using TextEncoder
and TextDecoder
before processing:
createStringDelta(source: string, target: string): string
applyStringDelta(origin: string, delta: string, options?: Options): string
getStringDeltaTargetSize(delta: string): number
Note that getStringDeltaTargetSize()
will return the size of the target string in UTF-8 bytes,
not characters (that is, it's not always equal to string
length of the resulting target).
I develop with Bun.
To build the library, run:
$ bun run build
npm, yarn will also work for building.
To run tests, run:
$ bun test
fossil-delta.js is now an ES module and there is no minified version included.
API renames:
create
->createDelta
apply
->applyDelta
outputSize
->getDeltaTargetSize
Important: createDelta
and applyDelta
now return the same type as the input (Uint8Array
if given Uint8Array
, Array
if given Array
), instead of always returning an Array
.