diff-app-1

import {useState} from 'react';

export const useInput = initialValue => {
    const [value, onChange] = useState(initialValue);

    return {
        value,
        onChange(e) {
            onChange(e.target.value);
        },
    };
};


import {tokenize, markEdits, pickRanges} from 'react-diff-view';
import {flatMap} from 'lodash';

const TOKEN_TYPE_SPACE = 'space';

const findLeadingRange = change => {
    const [spaces] = /^\s*/.exec(change.content);
    return spaces
        ? {
              type: TOKEN_TYPE_SPACE,
              lineNumber: change.lineNumber,
              start: 0,
              length: spaces.length,
              properties: {value: spaces},
          }
        : null;
};

const findTrailingRange = change => {
    const [spaces] = /\s*$/.exec(change.content);
    return spaces
        ? {
              type: TOKEN_TYPE_SPACE,
              lineNumber: change.lineNumber,
              start: change.content.length - spaces.length,
              length: spaces.length,
              properties: {value: spaces},
          }
        : null;
};

const pickLeadingAndTrailingSpaces = hunks => {
    const changes = flatMap(hunks, hunk => hunk.changes);
    const [oldRanges, newRanges] = changes.reduce(
        ([oldRanges, newRanges], change) => {
            const leadingRange = findLeadingRange(change);
            const trailingRange = findTrailingRange(change);
            const pushRange = ranges => {
                leadingRange && ranges.push(leadingRange);
                trailingRange && ranges.push(trailingRange);
            };

            if (!change.isInsert) {
                pushRange(oldRanges);
            }
            if (!change.isDelete) {
                pushRange(newRanges);
            }

            return [oldRanges, newRanges];
        },
        [[], []],
    );
    return pickRanges(oldRanges, newRanges);
};

export default hunks => {
    if (!hunks) {
        return undefined;
    }

    const options = {
        highlight: false,
        enhancers: [markEdits(hunks, {type: 'block'}), pickLeadingAndTrailingSpaces(hunks)],
    };

    try {
        return tokenize(hunks, options);
    } catch (ex) {
        return undefined;
    }
};