@20minutes/draft-convert/dist/util/updateMutation.js

Extensibly serialize & deserialize Draft.js ContentState

"use strict";
Object.defineProperty(exports, "__esModule", {
    value: true
});
Object.defineProperty(exports, "default", {
    enumerable: true,
    get: function() {
        return updateMutation;
    }
});
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;
}