overleaf/services/document-updater/app/js/DiffCodec.js
2020-12-07 15:30:02 -05:00

37 lines
871 B
JavaScript

const { diff_match_patch: DMP } = require('../lib/diff_match_patch')
const dmp = new DMP()
module.exports = {
ADDED: 1,
REMOVED: -1,
UNCHANGED: 0,
diffAsShareJsOp(before, after, callback) {
const diffs = dmp.diff_main(before.join('\n'), after.join('\n'))
dmp.diff_cleanupSemantic(diffs)
const ops = []
let position = 0
for (const diff of diffs) {
const type = diff[0]
const content = diff[1]
if (type === this.ADDED) {
ops.push({
i: content,
p: position
})
position += content.length
} else if (type === this.REMOVED) {
ops.push({
d: content,
p: position
})
} else if (type === this.UNCHANGED) {
position += content.length
} else {
throw new Error('Unknown type')
}
}
callback(null, ops)
}
}