756d562c66
* Format JSON files. Currently we store JSON as a single line in files. We should prettify it like we do the other formats. * Add output parsers to the frontmatter list. * Cleanup frontmatter format parser options. * Support writing frontmatter in TOML and JSON. Right now we can read TOML or JSON frontmatter by inferring, but we can only write frontmatter in YAML. This change allows the frontmatter format to be explicitly set for reading and writing. * Fix frontmatter formatter. * Update Frontmatter formatter tests. * Update frontmatter format docs.
91 lines
2.8 KiB
JavaScript
91 lines
2.8 KiB
JavaScript
import matter from 'gray-matter';
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import tomlFormatter from './toml';
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import yamlFormatter from './yaml';
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import jsonFormatter from './json';
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const parsers = {
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toml: {
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parse: input => tomlFormatter.fromFile(input),
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stringify: (metadata, { sortedKeys }) => tomlFormatter.toFile(metadata, sortedKeys),
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},
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json: {
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parse: 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 jsonFormatter.fromFile(JSONinput);
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},
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stringify: (metadata, { sortedKeys }) => {
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let JSONoutput = jsonFormatter.toFile(metadata, sortedKeys).trim();
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// Trim leading and trailing brackets.
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if (JSONoutput.substr(0, 1) === '{' && JSONoutput.substr(-1) === '}') {
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JSONoutput = JSONoutput.substring(1, JSONoutput.length - 1);
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}
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return JSONoutput;
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},
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},
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yaml: {
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parse: input => yamlFormatter.fromFile(input),
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stringify: (metadata, { sortedKeys }) => yamlFormatter.toFile(metadata, sortedKeys),
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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 getFormatOpts('yaml');
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case "+++":
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return getFormatOpts('toml');
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case "{":
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return getFormatOpts('json');
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default:
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throw "Unrecognized front-matter format.";
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}
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}
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export const getFormatOpts = format => ({
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yaml: { language: "yaml", delimiters: "---" },
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toml: { language: "toml", delimiters: "+++" },
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json: { language: "json", delimiters: ["{", "}"] },
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}[format]);
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class FrontmatterFormatter {
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constructor(format) {
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this.format = getFormatOpts(format);
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}
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fromFile(content) {
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const format = this.format || inferFrontmatterFormat(content);
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const result = matter(content, { engines: parsers, ...format });
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return {
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...result.data,
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body: result.content,
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};
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}
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toFile(data, sortedKeys) {
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const { body = '', ...meta } = data;
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// Stringify to YAML if the format was not set
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const format = this.format || getFormatOpts('yaml');
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// `sortedKeys` is not recognized by gray-matter, so it gets passed through to the parser
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return matter.stringify(body, meta, { engines: parsers, sortedKeys, ...format });
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}
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}
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export const FrontmatterInfer = new FrontmatterFormatter();
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export const FrontmatterYAML = new FrontmatterFormatter('yaml');
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export const FrontmatterTOML = new FrontmatterFormatter('toml');
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export const FrontmatterJSON = new FrontmatterFormatter('json');
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