Generates a set of Sanity patches needed to change an item (usually a document) from one shape to another
npm install sanity-diff-patch
Generates a set of Sanity patch mutations needed to change an item (usually a document) from one shape to another.
Most values will become simple set, unset or insert operations, but it will also (by default) try to use diff-match-patch for strings (read more).
An ifRevisionID constraint can be given to generate patches that include this revision as a safeguard, to prevent modifying documents that has changed since the diff was generated.
The document ID used in the patches is either extracted from item A and item B (_id property), or can be set explicitly by using the id option. This is _required_ if the _id property differs in the two items, to prevent patching the wrong document.
If encountering undefined values within an array, they will be converted to null values and print a warning to the console. Should you want to remove undefined values from arrays, manually remove them from the array prior to diffing (array.filter(item => typeof item === 'undefined') is your friend).
npm install --save sanity-diff-patch
``js
import {diffPatch} from 'sanity-diff-patch'
const patch = diffPatch(itemA, itemB)
/*
[
{patch: {id: 'docId', set: {...}}},
{patch: {id: 'docId', unset: [...]}},
{patch: {id: 'docId', insert: {...}}}
]
*/
`
`js
import {diffPatch} from 'sanity-diff-patch'
import sanityClient from './myConfiguredSanityClient'
const itemA = {
_id: 'die-hard-iii',
_type: 'movie',
_rev: 'k0k0s',
name: 'Die Hard 3',
year: 1995,
characters: [
{
_key: 'ma4sg31',
name: 'John McClane'
},
{
_key: 'l13ma92',
name: 'Simon Gruber'
}
]
}
const itemB = {
_id: 'drafts.die-hard-iii',
_type: 'movie',
name: 'Die Hard with a Vengeance',
characters: [
{
_key: 'ma4sg31',
name: 'John McClane'
},
{
_key: 'l13ma92',
name: 'Simon Grüber'
}
]
}
// Specify id if the two documents do not match
const operations = diffPatch(itemA, itemB, {id: itemA._id, ifRevisionID: itemA._rev})
await sanityClient.transaction(operations).commit()
// Patches generated:
const generatedPatches = [
{
patch: {
id: 'die-hard-iii',
ifRevisionID: 'k0k0s',
set: {
'name': 'Die Hard with a Vengeance',
'characters[_key=="l13ma92"].name': 'Simon Grüber'
},
}
},
{
patch: {
id: 'die-hard-iii',
unset: ['year']
}
}
}
`
When encountering two strings to compare, this module will (by default) attempt to use diff-match-patch (DMP) to transition the string from one state to the next.
While these patches are extremely helpful (especially in a real-time, collaborative environment), they sometimes grow quite large and can be hard for humans to read. There are a few options you can use to tweak _when_ this module will use these patches, and when to fall back to a regular set-patch instead.
The default rules says:
- If the target string is below 30 characters long, don't use DMP
- If the generated DMP is greater than 1.2 times larger than the target string, don't use DMP
To tune these rules, you can pass options to the differ:
`js
import {diffPatch} from 'sanity-diff-patch'
diffPatch(itemA, itemB, {
diffMatchPatch: {
// Default is true, set to false to _always_ use set-patches
enabled: true,
// Only use diff-match-patch if target string is longer than this threshold
lengthThresholdAbsolute: 30,
// Only use generated diff-match-patch if the patch length is less than or equal to
// (targetString * relative). Example: A 100 character target with a relative factor
// of 1.2 will allow a 120 character diff-match-patch. If larger than this number,
// it will fall back to a regular set patch.`
lengthThresholdRelative: 1.2
}
})
In addition to these rules, there are certain cases where it will never use diff-match-patch:
- If the patched key starts with an underscore (eg _type, _key, _ref`)
- If the diff-match-patch implementation cannot generate a legal patch due to unicode issues
- Improve patch on array item move
- Improve patch on array item delete
MIT © Espen Hovlandsdal