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44 lines
1.3 KiB
TypeScript
44 lines
1.3 KiB
TypeScript
// Copyright 2018-2024 the Deno authors. All rights reserved. MIT license.
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import { type Format, RECOGNIZE_REGEXP_MAP } from "./_formats.ts";
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import type { Extract } from "./types.ts";
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/** Parser function type */
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export type Parser = <T = Record<string, unknown>>(str: string) => T;
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export function extractAndParse<T>(
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input: string,
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extractRegExp: RegExp,
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parse: Parser,
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): Extract<T> {
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const match = extractRegExp.exec(input);
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if (!match || match.index !== 0) {
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throw new TypeError("Unexpected end of input");
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}
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const frontMatter = match.at(-1)?.replace(/^\s+|\s+$/g, "") || "";
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const attrs = parse(frontMatter) as T;
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const body = input.replace(match[0], "");
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return { frontMatter, body, attrs };
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}
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/**
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* Recognizes the format of the front matter in a string.
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* Supports {@link https://yaml.org | YAML}, {@link https://toml.io | TOML} and
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* {@link https://www.json.org/ | JSON}.
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*
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* @param str String to recognize.
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* @param formats A list of formats to recognize. Defaults to all supported formats.
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*/
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export function recognize(
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str: string,
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formats: Format[],
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): Format {
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const [firstLine] = str.split(/(\r?\n)/) as [string];
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for (const format of formats) {
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if (RECOGNIZE_REGEXP_MAP.get(format)?.test(firstLine)) return format;
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}
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throw new TypeError("Unsupported front matter format");
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}
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