# tools/core/transformers/venue.transformer.ts

> 46 lines of code and 16 definitions.

Tree: Coordination tree
Language: typescript
Layer: processing
Canonical: https://banes-lab.com/anatomy/coordination#file-coordination-tools-core-transformers-venue-transformer-ts
Source text: https://banes-lab.com/source/coordination/tools/core/transformers/venue.transformer.ts.txt

Listed in [tools/core/transformers](https://banes-lab.com/api/source/coordination/tools/core/transformers.md), after [tools/core/transformers/segment.transformer.ts](https://banes-lab.com/source/coordination/tools/core/transformers/segment.transformer.ts.md).

## Definitions

- `SUCCESSOR_FIELD` (lexical_declaration, line 4, exported)
- `SECTION_HEADING` (lexical_declaration, line 6)
- `SUCCESSOR_WORD` (lexical_declaration, line 8)
- `successorSectionClose` (lexical_declaration, line 10)
- `ends` (lexical_declaration, line 22)
- `successorWritten` (lexical_declaration, line 30, exported)
- `fenced` (lexical_declaration, line 31, exported)
- `lines` (lexical_declaration, line 32, exported)
- `at` (lexical_declaration, line 33, exported)
- `close` (lexical_declaration, line 38, exported)
- `lastInheritedItem` (lexical_declaration, line 42, exported)
- `trimmed` (lexical_declaration, line 43, exported)
- `opens` (lexical_declaration, line 44, exported)
- `first` (lexical_declaration, line 45, exported)
- `closes` (lexical_declaration, line 50, exported)
- `end` (lexical_declaration, line 53, exported)

## Source

```typescript
import { INHERITED_BANNER, LIST_MARKER } from "../constants/blocking.constants.ts";
import { fencedFlags } from "../predicates/fence.predicate.ts";

export const SUCCESSOR_FIELD = "SUCCESSOR:";

const SECTION_HEADING = "## ";

const SUCCESSOR_WORD = "SUCCESSOR";

const successorSectionClose = function successorSectionClose(
    lines: readonly string[],
    fenced: readonly boolean[],
): number {
    const opens = lines.findIndex((line) => {
        const trimmed = line.trim();
        return trimmed.startsWith(SECTION_HEADING) && trimmed.includes(SUCCESSOR_WORD);
    });
    if (opens === -1) {
        return -1;
    }

    const ends = lines.findIndex((line, index) => {
        const trimmed = line.trim();
        return index > opens && trimmed.startsWith(SECTION_HEADING) && !trimmed.includes(SUCCESSOR_WORD);
    });
    const end = ends === -1 ? lines.length : ends;
    return fenced.findLastIndex((flag, index) => flag && index > opens && index < end);
};

export const successorWritten = function successorWritten(before: string, declaration: string): string | null {
    const fenced = fencedFlags(before);
    const lines = before.split("\n");
    const at = lines.findIndex((line, index) => fenced[index] !== true && line.trim().startsWith(SUCCESSOR_FIELD));
    if (at !== -1) {
        return [...lines.slice(0, at), declaration, ...lines.slice(at + 1)].join("\n");
    }

    const close = successorSectionClose(lines, fenced);
    return close === -1 ? null : [...lines.slice(0, close + 1), "", declaration, ...lines.slice(close + 1)].join("\n");
};

export const lastInheritedItem = function lastInheritedItem(lines: readonly string[]): number {
    const trimmed = lines.map((line) => line.trim());
    const opens = trimmed.findIndex((line) => line.startsWith(INHERITED_BANNER));
    const first = trimmed.findIndex((line, index) => index > opens && line.startsWith(LIST_MARKER));
    if (opens === -1 || first === -1) {
        return -1;
    }

    const closes = trimmed.findIndex(
        (line, index) => index > first && line.startsWith("═") && !line.startsWith(INHERITED_BANNER),
    );
    const end = closes === -1 ? trimmed.length : closes;
    return trimmed.findLastIndex((line, index) => index >= first && index < end && line.startsWith(LIST_MARKER));
};
```