devsite/node_modules/gray-matter/index.js

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2024-07-08 01:49:38 +00:00
'use strict';
const fs = require('fs');
const sections = require('section-matter');
const defaults = require('./lib/defaults');
const stringify = require('./lib/stringify');
const excerpt = require('./lib/excerpt');
const engines = require('./lib/engines');
const toFile = require('./lib/to-file');
const parse = require('./lib/parse');
const utils = require('./lib/utils');
/**
* Takes a string or object with `content` property, extracts
* and parses front-matter from the string, then returns an object
* with `data`, `content` and other [useful properties](#returned-object).
*
* ```js
* const matter = require('gray-matter');
* console.log(matter('---\ntitle: Home\n---\nOther stuff'));
* //=> { data: { title: 'Home'}, content: 'Other stuff' }
* ```
* @param {Object|String} `input` String, or object with `content` string
* @param {Object} `options`
* @return {Object}
* @api public
*/
function matter(input, options) {
if (input === '') {
return { data: {}, content: input, excerpt: '', orig: input };
}
let file = toFile(input);
const cached = matter.cache[file.content];
if (!options) {
if (cached) {
file = Object.assign({}, cached);
file.orig = cached.orig;
return file;
}
// only cache if there are no options passed. if we cache when options
// are passed, we would need to also cache options values, which would
// negate any performance benefits of caching
matter.cache[file.content] = file;
}
return parseMatter(file, options);
}
/**
* Parse front matter
*/
function parseMatter(file, options) {
const opts = defaults(options);
const open = opts.delimiters[0];
const close = '\n' + opts.delimiters[1];
let str = file.content;
if (opts.language) {
file.language = opts.language;
}
// get the length of the opening delimiter
const openLen = open.length;
if (!utils.startsWith(str, open, openLen)) {
excerpt(file, opts);
return file;
}
// if the next character after the opening delimiter is
// a character from the delimiter, then it's not a front-
// matter delimiter
if (str.charAt(openLen) === open.slice(-1)) {
return file;
}
// strip the opening delimiter
str = str.slice(openLen);
const len = str.length;
// use the language defined after first delimiter, if it exists
const language = matter.language(str, opts);
if (language.name) {
file.language = language.name;
str = str.slice(language.raw.length);
}
// get the index of the closing delimiter
let closeIndex = str.indexOf(close);
if (closeIndex === -1) {
closeIndex = len;
}
// get the raw front-matter block
file.matter = str.slice(0, closeIndex);
const block = file.matter.replace(/^\s*#[^\n]+/gm, '').trim();
if (block === '') {
file.isEmpty = true;
file.empty = file.content;
file.data = {};
} else {
// create file.data by parsing the raw file.matter block
file.data = parse(file.language, file.matter, opts);
}
// update file.content
if (closeIndex === len) {
file.content = '';
} else {
file.content = str.slice(closeIndex + close.length);
if (file.content[0] === '\r') {
file.content = file.content.slice(1);
}
if (file.content[0] === '\n') {
file.content = file.content.slice(1);
}
}
excerpt(file, opts);
if (opts.sections === true || typeof opts.section === 'function') {
sections(file, opts.section);
}
return file;
}
/**
* Expose engines
*/
matter.engines = engines;
/**
* Stringify an object to YAML or the specified language, and
* append it to the given string. By default, only YAML and JSON
* can be stringified. See the [engines](#engines) section to learn
* how to stringify other languages.
*
* ```js
* console.log(matter.stringify('foo bar baz', {title: 'Home'}));
* // results in:
* // ---
* // title: Home
* // ---
* // foo bar baz
* ```
* @param {String|Object} `file` The content string to append to stringified front-matter, or a file object with `file.content` string.
* @param {Object} `data` Front matter to stringify.
* @param {Object} `options` [Options](#options) to pass to gray-matter and [js-yaml].
* @return {String} Returns a string created by wrapping stringified yaml with delimiters, and appending that to the given string.
* @api public
*/
matter.stringify = function(file, data, options) {
if (typeof file === 'string') file = matter(file, options);
return stringify(file, data, options);
};
/**
* Synchronously read a file from the file system and parse
* front matter. Returns the same object as the [main function](#matter).
*
* ```js
* const file = matter.read('./content/blog-post.md');
* ```
* @param {String} `filepath` file path of the file to read.
* @param {Object} `options` [Options](#options) to pass to gray-matter.
* @return {Object} Returns [an object](#returned-object) with `data` and `content`
* @api public
*/
matter.read = function(filepath, options) {
const str = fs.readFileSync(filepath, 'utf8');
const file = matter(str, options);
file.path = filepath;
return file;
};
/**
* Returns true if the given `string` has front matter.
* @param {String} `string`
* @param {Object} `options`
* @return {Boolean} True if front matter exists.
* @api public
*/
matter.test = function(str, options) {
return utils.startsWith(str, defaults(options).delimiters[0]);
};
/**
* Detect the language to use, if one is defined after the
* first front-matter delimiter.
* @param {String} `string`
* @param {Object} `options`
* @return {Object} Object with `raw` (actual language string), and `name`, the language with whitespace trimmed
*/
matter.language = function(str, options) {
const opts = defaults(options);
const open = opts.delimiters[0];
if (matter.test(str)) {
str = str.slice(open.length);
}
const language = str.slice(0, str.search(/\r?\n/));
return {
raw: language,
name: language ? language.trim() : ''
};
};
/**
* Expose `matter`
*/
matter.cache = {};
matter.clearCache = function() {
matter.cache = {};
};
module.exports = matter;