🎉 initiate project *astro_rewrite*

node_modules/micromark-extension-frontmatter/matters.js

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+/**
+ * @typedef {'toml' | 'yaml'} Preset
+ *   Known name of a frontmatter style.
+ *
+ * @typedef Info
+ *   Sequence.
+ *
+ *   Depending on how this structure is used, it reflects a marker or a fence.
+ * @property {string} open
+ *   Opening.
+ * @property {string} close
+ *   Closing.
+ *
+ * @typedef MatterProps
+ *   Fields describing a kind of matter.
+ * @property {string} type
+ *   Node type to tokenize as.
+ * @property {boolean | null | undefined} [anywhere=false]
+ *   Whether matter can be found anywhere in the document, normally, only matter
+ *   at the start of the document is recognized.
+ *
+ *   > 👉 **Note**: using this is a terrible idea.
+ *   > It’s called frontmatter, not matter-in-the-middle or so.
+ *   > This makes your markdown less portable.
+ *
+ * @typedef MarkerProps
+ *   Marker configuration.
+ * @property {Info | string} marker
+ *   Character repeated 3 times, used as complete fences.
+ *
+ *   For example the character `'-'` will result in `'---'` being used as the
+ *   fence
+ *   Pass `open` and `close` to specify different characters for opening and
+ *   closing fences.
+ * @property {never} [fence]
+ *   If `marker` is set, `fence` must not be set.
+ *
+ * @typedef FenceProps
+ *   Fence configuration.
+ * @property {Info | string} fence
+ *   Complete fences.
+ *
+ *   This can be used when fences contain different characters or lengths
+ *   other than 3.
+ *   Pass `open` and `close` to interface to specify different characters for opening and
+ *   closing fences.
+ * @property {never} [marker]
+ *   If `fence` is set, `marker` must not be set.
+ *
+ * @typedef {(MatterProps & FenceProps) | (MatterProps & MarkerProps)} Matter
+ *   Fields describing a kind of matter.
+ *
+ *   > 👉 **Note**: using `anywhere` is a terrible idea.
+ *   > It’s called frontmatter, not matter-in-the-middle or so.
+ *   > This makes your markdown less portable.
+ *
+ *   > 👉 **Note**: `marker` and `fence` are mutually exclusive.
+ *   > If `marker` is set, `fence` must not be set, and vice versa.
+ *
+ * @typedef {Matter | Preset | Array<Matter | Preset>} Options
+ *   Configuration.
+ */
+
+import {fault} from 'fault'
+const own = {}.hasOwnProperty
+const markers = {
+  yaml: '-',
+  toml: '+'
+}
+
+/**
+ * Simplify one or more options.
+ *
+ * @param {Options | null | undefined} [options='yaml']
+ *   Configuration.
+ * @returns {Array<Matter>}
+ *   List of matters.
+ */
+export function matters(options) {
+  /** @type {Array<Matter>} */
+  const result = []
+  let index = -1
+
+  /** @type {Array<Matter | Preset>} */
+  const presetsOrMatters = Array.isArray(options)
+    ? options
+    : options
+    ? [options]
+    : ['yaml']
+  while (++index < presetsOrMatters.length) {
+    result[index] = matter(presetsOrMatters[index])
+  }
+  return result
+}
+
+/**
+ * Simplify an option.
+ *
+ * @param {Matter | Preset} option
+ *   Configuration.
+ * @returns {Matter}
+ *   Matters.
+ */
+function matter(option) {
+  let result = option
+  if (typeof result === 'string') {
+    if (!own.call(markers, result)) {
+      throw fault('Missing matter definition for `%s`', result)
+    }
+    result = {
+      type: result,
+      marker: markers[result]
+    }
+  } else if (typeof result !== 'object') {
+    throw fault('Expected matter to be an object, not `%j`', result)
+  }
+  if (!own.call(result, 'type')) {
+    throw fault('Missing `type` in matter `%j`', result)
+  }
+  if (!own.call(result, 'fence') && !own.call(result, 'marker')) {
+    throw fault('Missing `marker` or `fence` in matter `%j`', result)
+  }
+  return result
+}