Docs

1 files changed, 167 insertions, 0 deletions

diff --git a/node_modules/tailwindcss/src/util/pseudoElements.js b/node_modules/tailwindcss/src/util/pseudoElements.js
new file mode 100644
index 0000000..5795cdd
--- /dev/null
+++ b/node_modules/tailwindcss/src/util/pseudoElements.js
@@ -0,0 +1,167 @@
+/** @typedef {import('postcss-selector-parser').Root} Root */
+/** @typedef {import('postcss-selector-parser').Selector} Selector */
+/** @typedef {import('postcss-selector-parser').Pseudo} Pseudo */
+/** @typedef {import('postcss-selector-parser').Node} Node */
+
+// There are some pseudo-elements that may or may not be:
+
+// **Actionable**
+// Zero or more user-action pseudo-classes may be attached to the pseudo-element itself
+// structural-pseudo-classes are NOT allowed but we don't make
+// The spec is not clear on whether this is allowed or not — but in practice it is.
+
+// **Terminal**
+// It MUST be placed at the end of a selector
+//
+// This is the required in the spec. However, some pseudo elements are not "terminal" because
+// they represent a "boundary piercing" that is compiled out by a build step.
+
+// **Jumpable**
+// Any terminal element may "jump" over combinators when moving to the end of the selector
+//
+// This is a backwards-compat quirk of pseudo element variants from earlier versions of Tailwind CSS.
+
+/** @typedef {'terminal' | 'actionable' | 'jumpable'} PseudoProperty */
+
+/** @type {Record<string, PseudoProperty[]>} */
+let elementProperties = {
+  // Pseudo elements from the spec
+  '::after': ['terminal', 'jumpable'],
+  '::backdrop': ['terminal', 'jumpable'],
+  '::before': ['terminal', 'jumpable'],
+  '::cue': ['terminal'],
+  '::cue-region': ['terminal'],
+  '::first-letter': ['terminal', 'jumpable'],
+  '::first-line': ['terminal', 'jumpable'],
+  '::grammar-error': ['terminal'],
+  '::marker': ['terminal', 'jumpable'],
+  '::part': ['terminal', 'actionable'],
+  '::placeholder': ['terminal', 'jumpable'],
+  '::selection': ['terminal', 'jumpable'],
+  '::slotted': ['terminal'],
+  '::spelling-error': ['terminal'],
+  '::target-text': ['terminal'],
+
+  // Pseudo elements from the spec with special rules
+  '::file-selector-button': ['terminal', 'actionable'],
+
+  // Library-specific pseudo elements used by component libraries
+  // These are Shadow DOM-like
+  '::deep': ['actionable'],
+  '::v-deep': ['actionable'],
+  '::ng-deep': ['actionable'],
+
+  // Note: As a rule, double colons (::) should be used instead of a single colon
+  // (:). This distinguishes pseudo-classes from pseudo-elements. However, since
+  // this distinction was not present in older versions of the W3C spec, most
+  // browsers support both syntaxes for the original pseudo-elements.
+  ':after': ['terminal', 'jumpable'],
+  ':before': ['terminal', 'jumpable'],
+  ':first-letter': ['terminal', 'jumpable'],
+  ':first-line': ['terminal', 'jumpable'],
+
+  // The default value is used when the pseudo-element is not recognized
+  // Because it's not recognized, we don't know if it's terminal or not
+  // So we assume it can be moved AND can have user-action pseudo classes attached to it
+  __default__: ['terminal', 'actionable'],
+}
+
+/**
+ * @param {Selector} sel
+ * @returns {Selector}
+ */
+export function movePseudos(sel) {
+  let [pseudos] = movablePseudos(sel)
+
+  // Remove all pseudo elements from their respective selectors
+  pseudos.forEach(([sel, pseudo]) => sel.removeChild(pseudo))
+
+  // Re-add them to the end of the selector in the correct order.
+  // This moves terminal pseudo elements to the end of the
+  // selector otherwise the selector will not be valid.
+  //
+  // Examples:
+  //  - `before:hover:text-center` would result in `.before\:hover\:text-center:hover::before`
+  //  - `hover:before:text-center` would result in `.hover\:before\:text-center:hover::before`
+  //
+  // The selector `::before:hover` does not work but we
+  // can make it work for you by flipping the order.
+  sel.nodes.push(...pseudos.map(([, pseudo]) => pseudo))
+
+  return sel
+}
+
+/** @typedef {[sel: Selector, pseudo: Pseudo, attachedTo: Pseudo | null]} MovablePseudo */
+/** @typedef {[pseudos: MovablePseudo[], lastSeenElement: Pseudo | null]} MovablePseudosResult */
+
+/**
+ * @param {Selector} sel
+ * @returns {MovablePseudosResult}
+ */
+function movablePseudos(sel) {
+  /** @type {MovablePseudo[]} */
+  let buffer = []
+
+  /** @type {Pseudo | null} */
+  let lastSeenElement = null
+
+  for (let node of sel.nodes) {
+    if (node.type === 'combinator') {
+      buffer = buffer.filter(([, node]) => propertiesForPseudo(node).includes('jumpable'))
+      lastSeenElement = null
+    } else if (node.type === 'pseudo') {
+      if (isMovablePseudoElement(node)) {
+        lastSeenElement = node
+        buffer.push([sel, node, null])
+      } else if (lastSeenElement && isAttachablePseudoClass(node, lastSeenElement)) {
+        buffer.push([sel, node, lastSeenElement])
+      } else {
+        lastSeenElement = null
+      }
+
+      for (let sub of node.nodes ?? []) {
+        let [movable, lastSeenElementInSub] = movablePseudos(sub)
+        lastSeenElement = lastSeenElementInSub || lastSeenElement
+        buffer.push(...movable)
+      }
+    }
+  }
+
+  return [buffer, lastSeenElement]
+}
+
+/**
+ * @param {Node} node
+ * @returns {boolean}
+ */
+function isPseudoElement(node) {
+  return node.value.startsWith('::') || elementProperties[node.value] !== undefined
+}
+
+/**
+ * @param {Node} node
+ * @returns {boolean}
+ */
+function isMovablePseudoElement(node) {
+  return isPseudoElement(node) && propertiesForPseudo(node).includes('terminal')
+}
+
+/**
+ * @param {Node} node
+ * @param {Pseudo} pseudo
+ * @returns {boolean}
+ */
+function isAttachablePseudoClass(node, pseudo) {
+  if (node.type !== 'pseudo') return false
+  if (isPseudoElement(node)) return false
+
+  return propertiesForPseudo(pseudo).includes('actionable')
+}
+
+/**
+ * @param {Pseudo} pseudo
+ * @returns {PseudoProperty[]}
+ */
+function propertiesForPseudo(pseudo) {
+  return elementProperties[pseudo.value] ?? elementProperties.__default__
+}