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forked from mirror/misskey
misskey/src/mfm/normalize.ts
2020-04-04 08:46:54 +09:00

32 lines
1.1 KiB
TypeScript

import * as A from '../prelude/array';
import * as S from '../prelude/string';
import { MfmForest, MfmTree } from './prelude';
import { createTree, createLeaf } from '../prelude/tree';
function isEmptyTextTree(t: MfmTree): boolean {
return t.node.type === 'text' && t.node.props.text === '';
}
function concatTextTrees(ts: MfmForest): MfmTree {
return createLeaf({ type: 'text', props: { text: S.concat(ts.map(x => x.node.props.text)) } });
}
function concatIfTextTrees(ts: MfmForest): MfmForest {
return ts[0].node.type === 'text' ? [concatTextTrees(ts)] : ts;
}
function concatConsecutiveTextTrees(ts: MfmForest): MfmForest {
const us = A.concat(A.groupOn(t => t.node.type, ts).map(concatIfTextTrees));
return us.map(t => createTree(t.node, concatConsecutiveTextTrees(t.children)));
}
function removeEmptyTextNodes(ts: MfmForest): MfmForest {
return ts
.filter(t => !isEmptyTextTree(t))
.map(t => createTree(t.node, removeEmptyTextNodes(t.children)));
}
export function normalize(ts: MfmForest): MfmForest {
return removeEmptyTextNodes(concatConsecutiveTextTrees(ts));
}