mirror of
https://github.com/yjs/yjs.git
synced 2025-12-16 03:37:50 +01:00
196 lines
8.3 KiB
JavaScript
196 lines
8.3 KiB
JavaScript
import * as Y from '../src/index.js'
|
|
import * as delta from 'lib0/delta'
|
|
import * as t from 'lib0/testing'
|
|
import * as s from 'lib0/schema'
|
|
|
|
/**
|
|
* Delta is a versatyle format enabling you to efficiently describe changes. It is part of lib0, so
|
|
* that non-yjs applications can use it without consuming the full Yjs package. It is well suited
|
|
* for efficiently describing state & changesets.
|
|
*
|
|
* Assume we start with the text "hello world". Now we want to delete " world" and add an
|
|
* exclamation mark. The final content should be "hello!" ("hello world" => "hello!")
|
|
*
|
|
* In most editors, you would describe the necessary changes as replace operations using indexes.
|
|
* However, this might become ambiguous when many changes are involved.
|
|
*
|
|
* - delete range 5-11
|
|
* - insert "!" at position 11
|
|
*
|
|
* Using the delta format, you can describe the changes similar to what you would do in an text editor.
|
|
* The "|" describes the current cursor position.
|
|
*
|
|
* - d.retain(5) - "|hello world" => "hello| world" - jump over the next five characters
|
|
* - d.delete(6) - "hello| world" => "hello|" - delete the next 6 characres
|
|
* - d.insert('!') - "hello!|" - insert "!" at the current position
|
|
* => compact form: d.retain(5).delete(6).insert('!')
|
|
*
|
|
* You can also apply the changes in two distinct steps and then rebase the op so that you can apply
|
|
* them in two distinct steps.
|
|
* - delete " world": d1 = delta.create().retain(5).delete(6)
|
|
* - insert "!": d2 = delta.create().retain(11).insert('!')
|
|
* - rebase d2 on-top of d1: d2.rebase(d1) == delta.create().retain(5).insert('!')
|
|
* - merge into a single change: d1.apply(d2) == delta.create().retain(5).delete(6).insert(!)
|
|
*
|
|
* @param {t.TestCase} _tc
|
|
*/
|
|
export const testDeltaBasics = _tc => {
|
|
// the state of our text document
|
|
const state = delta.create().insert('hello world')
|
|
// describe changes: delete " world" & insert "!"
|
|
const change = delta.create().retain(5).delete(6).insert('!')
|
|
// apply changes to state
|
|
state.apply(change)
|
|
// compare state to expected state
|
|
t.assert(state.equals(delta.create().insert('hello!')))
|
|
}
|
|
|
|
/**
|
|
* lib0 also ships a schema library that can be used to validate JSON objects and custom data types,
|
|
* like Yjs types.
|
|
*
|
|
* As a convention, schemas are usually prefixed with a $ sign. This clarifies the difference
|
|
* between a schema, and an instance of a schema.
|
|
*
|
|
* const $myobj = s.$object({ key: s.$number })
|
|
* let inputValue: any
|
|
* if ($myobj.check(inputValue)) {
|
|
* inputValue // is validated and of type $myobj
|
|
* }
|
|
*
|
|
* We can also define the expected values on a delta.
|
|
*
|
|
* @param {t.TestCase} _tc
|
|
*/
|
|
export const testDeltaBasicSchema = _tc => {
|
|
const $d = delta.$delta({ attrs: s.$object({ key: s.$string }), children: s.$number, hasText: false })
|
|
const d = delta.create($d)
|
|
// @ts-expect-error
|
|
d.set('key', false) // invalid change: will throw a type error
|
|
t.fails(() => {
|
|
// @ts-expect-error
|
|
d.apply(delta.create().set('key', false)) // invalid delta: will throw a type error
|
|
})
|
|
}
|
|
|
|
/**
|
|
* Deltas can describe changes on attributes and children. Textual insertions are children. But we
|
|
* may also insert json-objects and other deltas as children.
|
|
* Key-value pairs can be represented as attributes. This "convoluted" changeset enables us to
|
|
* describe many changes in the same breath:
|
|
*
|
|
* delta.create().set('a', 42).retain(5).delete(6).insert('!').unset('b')
|
|
*
|
|
* @param {t.TestCase} _tc
|
|
*/
|
|
export const testDeltaValues = _tc => {
|
|
const change = delta.create().set('a', 42).unset('b').retain(5).delete(6).insert('!').insert([{ my: 'custom object' }])
|
|
// iterate through attribute changes
|
|
for (const attrChange of change.attrs) {
|
|
if (delta.$insertOp.check(attrChange)) {
|
|
console.log(`set ${attrChange.key} to ${attrChange.value}`)
|
|
} else if (delta.$deleteOp.check(attrChange)) {
|
|
console.log(`delete ${attrChange.key}`)
|
|
}
|
|
}
|
|
// iterate through child changes
|
|
for (const childChange of change.children) {
|
|
if (delta.$retainOp.check(childChange)) {
|
|
console.log(`retain ${childChange.retain} child items`)
|
|
} else if (delta.$deleteOp.check(childChange)) {
|
|
console.log(`delete ${childChange.delete} child items`)
|
|
} else if (delta.$insertOp.check(childChange)) {
|
|
console.log('insert child items:', childChange.insert)
|
|
} else if (delta.$textOp.check(childChange)) {
|
|
console.log('insert textual content', childChange.insert)
|
|
}
|
|
}
|
|
}
|
|
|
|
/**
|
|
* The new delta defines changes on attributes (key-value) and child elements (list & text), but can
|
|
* also be used to describe the current state of a document.
|
|
*
|
|
* 1. apply a delta to change a yjs type
|
|
* 2. observe deltas to read the differences
|
|
* 3. merge deltas to reflect multiple changes in a single delta
|
|
* 4. All Yjs types fully support the delta format. It is no longer necessary to define the type (such as Y.Array)
|
|
*
|
|
* @param {t.TestCase} _tc
|
|
*/
|
|
export const testBasics = _tc => {
|
|
const ydoc = new Y.Doc()
|
|
const ytype = ydoc.get('my data')
|
|
/**
|
|
* @type {delta.Delta<any,{ a: number }, { my: string }, string>}
|
|
*/
|
|
let observedDelta = delta.create()
|
|
ytype.observe(event => {
|
|
observedDelta = event.deltaDeep
|
|
console.log('ytype changed:', observedDelta.toJSON())
|
|
})
|
|
// define a change: set attribute: a=42
|
|
const attrChange = delta.create().set('a', 42).done()
|
|
// define a change: insert textual content and an object
|
|
const childChange = delta.create().insert('hello').insert([{ my: 'object' }]).done()
|
|
// merge changes
|
|
const mergedChanges = delta.create(delta.$deltaAny).apply(attrChange).apply(childChange).done()
|
|
console.log('merged changes: ', mergedChanges.toJSON())
|
|
ytype.applyDelta(mergedChanges)
|
|
// the observed change should equal the applied change
|
|
t.assert(observedDelta.equals(mergedChanges))
|
|
// read the current state of the yjs types as a delta
|
|
const currState = ytype.getContentDeep()
|
|
t.assert(currState.equals(mergedChanges)) // equal to the changes that we applied
|
|
}
|
|
|
|
/**
|
|
* Deltas allow us to describe the differences between two Yjs documents though "Attributions".
|
|
*
|
|
* - We can attribute changes to a user, or a group of users
|
|
* - There are 'insert', 'delete', and 'format' attributions
|
|
* - When we render attributions, we render inserted & deleted content as an insertions with special
|
|
* attributes which allow you to..
|
|
* -- Render deleted content using a strikethrough: I.e. `hello w̶o̶r̶l̶d̶!`
|
|
* -- Render attributed insertions using a background color.
|
|
*
|
|
* @param {t.TestCase} _tc
|
|
*/
|
|
export const testAttributions = _tc => {
|
|
const ydocV1 = new Y.Doc()
|
|
const ytypeV1 = ydocV1.get('txt')
|
|
ytypeV1.applyDelta(delta.create().insert('hello world'))
|
|
// create a new version with updated content
|
|
const ydoc = new Y.Doc()
|
|
Y.applyUpdate(ydoc, Y.encodeStateAsUpdate(ydocV1))
|
|
const ytype = ydoc.get('txt')
|
|
// delete " world" and insert exclamation mark "!".
|
|
ytype.applyDelta(delta.create().retain(5).delete(6).insert('!'))
|
|
const am = Y.createAttributionManagerFromDiff(ydocV1, ydoc)
|
|
// get the attributed differences
|
|
const attributedContent = ytype.getContent(am)
|
|
console.log('attributed content', attributedContent.toJSON())
|
|
t.assert(attributedContent.equals(delta.create().insert('hello').insert(' world', null, { delete: [] }).insert('!', null, { insert: [] })))
|
|
// for editor bindings, it is also necessary to observe changes and get the attributed changes
|
|
ytype.observe(event => {
|
|
const attributedChange = event.getDelta(am)
|
|
console.log('the attributed change', attributedChange.toJSON())
|
|
t.assert(attributedChange.equals(delta.create().retain(11).insert('!', null, { insert: [] })))
|
|
const unattributedChange = event.delta
|
|
console.log('the UNattributed change', unattributedChange.toJSON())
|
|
t.assert(unattributedChange.equals(delta.create().retain(5).insert('!')))
|
|
})
|
|
/**
|
|
* Content now has different representations.
|
|
* - The UNattributed representation renders the latest state, without history.
|
|
* - The attributed representation renders the differences.
|
|
*
|
|
* Attributed: 'hello<delete> world</delete><insert>!</insert>'
|
|
* UNattributed: 'world!'
|
|
*/
|
|
// Apply a change to the attributed content
|
|
ytype.applyDelta(delta.create().retain(11).insert('!'), am)
|
|
// // Equivalent to applying a change to the UNattributed content:
|
|
// ytype.applyDelta(delta.create().retain(5).insert('!'))
|
|
}
|