# core/matchers/target.matcher.ts

> 56 lines of code and 13 definitions.

Tree: GovLab Quality
Language: typescript
Layer: processing
Canonical: https://banes-lab.com/anatomy/quality#file-quality-core-matchers-target-matcher-ts
Source text: https://banes-lab.com/source/quality/core/matchers/target.matcher.ts.txt

Listed in [core/matchers](https://banes-lab.com/api/source/quality/core/matchers.md), after [core/matchers/exclusions.matcher.ts](https://banes-lab.com/source/quality/core/matchers/exclusions.matcher.ts.md) and before [core/matchers/word.matcher.ts](https://banes-lab.com/source/quality/core/matchers/word.matcher.ts.md).

## Definitions

- `esTokenYear` (lexical_declaration, line 24, exported)
- `isEsPrefix` (lexical_declaration, line 13)
- `yearOfVersion` (lexical_declaration, line 17)
- `findEsTokenSpans` (lexical_declaration, line 44)
- `spanAt` (lexical_declaration, line 35)
- `findStaleEsTokens` (lexical_declaration, line 57, exported)
- `rest` (lexical_declaration, line 28, exported)
- `close` (lexical_declaration, line 36)
- `token` (lexical_declaration, line 40)
- `spans` (lexical_declaration, line 45)
- `at` (lexical_declaration, line 46)
- `{ end, span }` (lexical_declaration, line 48)
- `year` (lexical_declaration, line 59, exported)

## Contained in

- [core/matchers](https://banes-lab.com/anatomy/quality/folder-quality-core-matchers.md)

## Linked from

- [core/matchers](https://banes-lab.com/anatomy/quality/folder-quality-core-matchers.md)

## Source

```typescript
import {
    ES_LEGACY_BASE,
    ES_LEGACY_MAX,
    ES_MODERN_BASE,
    ES_NEXT,
    ES_PREFIX_LEN,
    MIN_TOKEN_LEN,
    YEAR_THRESHOLD,
} from "#configuration/constants/target.constants";
import { everyChar, isDigit } from "@govlab/constants";
import type { EsTokenSpan } from "#types/target.types";

const isEsPrefix = function isEsPrefix(token: string): boolean {
    return token.slice(0, ES_PREFIX_LEN).toUpperCase() === "ES";
};

const yearOfVersion = function yearOfVersion(n: number): number {
    if (n >= YEAR_THRESHOLD) {
        return n;
    }
    return n <= ES_LEGACY_MAX ? ES_LEGACY_BASE + n : ES_MODERN_BASE + n;
};

export const esTokenYear = function esTokenYear(token: string): number | null {
    if (token.length < MIN_TOKEN_LEN || !isEsPrefix(token)) {
        return null;
    }
    const rest = token.slice(ES_PREFIX_LEN);
    if (rest.toLowerCase() === ES_NEXT) {
        return Number.POSITIVE_INFINITY;
    }
    return rest.length > 0 && everyChar(rest, isDigit) ? yearOfVersion(Number(rest)) : null;
};

const spanAt = function spanAt(text: string, open: number): { end: number; span: EsTokenSpan | null } {
    const close = text.indexOf('"', open + 1);
    if (close === -1) {
        return { end: text.length, span: null };
    }
    const token = text.slice(open + 1, close);
    return { end: close, span: esTokenYear(token) === null ? null : { close, open, token } };
};

const findEsTokenSpans = function findEsTokenSpans(text: string): EsTokenSpan[] {
    const spans: EsTokenSpan[] = [];
    let at = text.indexOf('"');
    while (at !== -1) {
        const { end, span } = spanAt(text, at);
        if (span !== null) {
            spans.push(span);
        }
        at = text.indexOf('"', end + 1);
    }
    return spans;
};

export const findStaleEsTokens = function findStaleEsTokens(text: string, minYear: number): EsTokenSpan[] {
    return findEsTokenSpans(text).filter((span) => {
        const year = esTokenYear(span.token);
        return year !== null && year < minYear;
    });
};
```