66 lines
1.7 KiB
JavaScript
66 lines
1.7 KiB
JavaScript
import matter from 'gray-matter';
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import tomlEng from 'toml';
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import YAML from './yaml';
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const parsers = {
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toml: tomlEng.parse.bind(tomlEng),
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json: (input) => {
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let JSONinput = input.trim();
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// Fix JSON if leading and trailing brackets were trimmed.
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if (JSONinput.substr(0, 1) !== '{') {
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JSONinput = '{' + JSONinput;
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}
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if (JSONinput.substr(-1) !== '}') {
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JSONinput = JSONinput + '}';
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}
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return matter.engines.json.parse(JSONinput);
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},
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}
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function inferFrontmatterFormat(str) {
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const firstLine = str.substr(0, str.indexOf('\n')).trim();
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if ((firstLine.length > 3) && (firstLine.substr(0, 3) === "---")) {
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// No need to infer, `gray-matter` will handle things like `---toml` for us.
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return;
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}
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switch (firstLine) {
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case "---":
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return { language: "yaml", delimiters: "---" };
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case "+++":
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return { language: "toml", delimiters: "+++" };
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case "{":
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return { language: "json", delimiters: ["{", "}"] };
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default:
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throw "Unrecgonized front-matter format.";
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}
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}
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export default class Frontmatter {
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fromFile(content) {
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const result = matter(content, { engines: parsers, ...inferFrontmatterFormat(content) });
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const data = result.data;
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data.body = result.content;
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return data;
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}
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toFile(data, sortedKeys) {
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const meta = {};
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let body = '';
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Object.keys(data).forEach((key) => {
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if (key === 'body') {
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body = data[key];
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} else {
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meta[key] = data[key];
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}
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});
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// always stringify to YAML
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const parser = {
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stringify(metadata) {
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return new YAML().toFile(metadata, sortedKeys);
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},
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};
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return matter.stringify(body, meta, { language: "yaml", delimiters: "---", engines: { yaml: parser } });
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}
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}
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