@20minutes/draft-convert
Version:
Extensibly serialize & deserialize Draft.js ContentState
59 lines (58 loc) • 2.59 kB
JavaScript
export default function updateMutation(mutation, originalOffset, originalLength, newLength, prefixLength, suffixLength) {
// three cases we can reasonably adjust - disjoint mutations that
// happen later on where the offset will need to be changed,
// mutations that completely contain the new one where we can adjust
// the length, and mutations that occur partially within the new one.
const lengthDiff = newLength - originalLength;
const mutationAfterChange = originalOffset + originalLength <= mutation.offset;
if (mutationAfterChange) {
return {
...mutation,
offset: mutation.offset + lengthDiff
};
}
const mutationContainsChange = originalOffset >= mutation.offset && originalOffset + originalLength <= mutation.offset + mutation.length;
if (mutationContainsChange) {
return {
...mutation,
length: mutation.length + lengthDiff
};
}
const mutationWithinPrefixChange = mutation.offset >= originalOffset && mutation.offset + mutation.length <= originalOffset + originalLength && prefixLength > 0;
if (mutationWithinPrefixChange) {
return {
...mutation,
offset: mutation.offset + prefixLength
};
}
const mutationContainsPrefix = mutation.offset < originalOffset && mutation.offset + mutation.length <= originalOffset + originalLength && mutation.offset + mutation.length > originalOffset && prefixLength > 0;
if (mutationContainsPrefix) {
return [
{
...mutation,
length: originalOffset - mutation.offset
},
{
...mutation,
offset: originalOffset + prefixLength,
length: mutation.offset - originalOffset + mutation.length
}
];
}
const mutationContainsSuffix = mutation.offset >= originalOffset && mutation.offset + mutation.length > originalOffset + originalLength && originalOffset + originalLength > mutation.offset && suffixLength > 0;
if (mutationContainsSuffix) {
return [
{
...mutation,
offset: mutation.offset + prefixLength,
length: originalOffset + originalLength - mutation.offset
},
{
...mutation,
offset: originalOffset + originalLength + prefixLength + suffixLength,
length: mutation.offset + mutation.length - (originalOffset + originalLength)
}
];
}
return mutation;
}