.

.editorconfig

@@ -0,0 +1,9 @@
+root = true
+
+[*]
+charset = utf-8
+end_of_line = lf
+indent_size = 2
+indent_style = space
+insert_final_newline = true
+trim_trailing_whitespace = true

.github/workflows/bb.yml

@@ -0,0 +1,13 @@
+jobs:
+  main:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: unifiedjs/beep-boop-beta@main
+        with:
+          repo-token: ${{secrets.GITHUB_TOKEN}}
+name: bb
+on:
+  issues:
+    types: [closed, edited, labeled, opened, reopened, unlabeled]
+  pull_request_target:
+    types: [closed, edited, labeled, opened, reopened, unlabeled]

.github/workflows/main.yml

@@ -0,0 +1,21 @@
+jobs:
+  main:
+    name: ${{matrix.node}}
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v4
+      - uses: actions/setup-node@v4
+        with:
+          node-version: ${{matrix.node}}
+      - run: npm install
+      - run: npm test
+      - uses: codecov/codecov-action@v4
+    strategy:
+      matrix:
+        node:
+          - lts/hydrogen
+          - node
+name: main
+on:
+  - pull_request
+  - push

.gitignore

@@ -0,0 +1,10 @@
+.DS_Store
+*.d.ts.map
+*.d.ts
+*.log
+*.tsbuildinfo
+coverage/
+node_modules/
+yarn.lock
+!/lib/types.d.ts
+!/index.d.ts

.npmrc

@@ -0,0 +1,2 @@
+ignore-scripts=true
+package-lock=false

.prettierignore

@@ -0,0 +1,3 @@
+coverage/
+*.html
+*.md

index.d.ts

@@ -0,0 +1,2 @@
+export type {Options} from './lib/types.js'
+export {format} from './lib/index.js'

index.js

@@ -0,0 +1,2 @@
+// Note: types exposed from `index.d.ts`.
+export {format} from './lib/index.js'

lib/index.js

@@ -0,0 +1,184 @@
+/**
+ * @import {Nodes, RootContent, Root} from 'hast'
+ * @import {BuildVisitor} from 'unist-util-visit-parents'
+ * @import {Options, State} from './types.js'
+ */
+
+import {embedded} from 'hast-util-embedded'
+import {minifyWhitespace} from 'hast-util-minify-whitespace'
+import {phrasing} from 'hast-util-phrasing'
+import {whitespace} from 'hast-util-whitespace'
+import {whitespaceSensitiveTagNames} from 'html-whitespace-sensitive-tag-names'
+import {SKIP, visitParents} from 'unist-util-visit-parents'
+
+/** @type {Options} */
+const emptyOptions = {}
+
+/**
+ * Format whitespace in HTML.
+ *
+ * @param {Root} tree
+ *   Tree.
+ * @param {Options | null | undefined} [options]
+ *   Configuration (optional).
+ * @returns {undefined}
+ *   Nothing.
+ */
+export function format(tree, options) {
+  const settings = options || emptyOptions
+
+  /** @type {State} */
+  const state = {
+    blanks: settings.blanks || [],
+    head: false,
+    indentInitial: settings.indentInitial !== false,
+    indent:
+      typeof settings.indent === 'number'
+        ? ' '.repeat(settings.indent)
+        : settings.indent || '  '
+  }
+
+  minifyWhitespace(tree, {newlines: true})
+
+  visitParents(tree, visitor)
+
+  /**
+   * @type {BuildVisitor<Root>}
+   */
+  function visitor(node, parents) {
+    if (!('children' in node)) {
+      return
+    }
+
+    if (node.type === 'element' && node.tagName === 'head') {
+      state.head = true
+    }
+
+    if (state.head && node.type === 'element' && node.tagName === 'body') {
+      state.head = false
+    }
+
+    if (
+      node.type === 'element' &&
+      whitespaceSensitiveTagNames.includes(node.tagName)
+    ) {
+      return SKIP
+    }
+
+    // Don’t indent content of whitespace-sensitive nodes / inlines.
+    if (node.children.length === 0 || !padding(state, node)) {
+      return
+    }
+
+    let level = parents.length
+
+    if (!state.indentInitial) {
+      level--
+    }
+
+    let eol = false
+
+    // Indent newlines in `text`.
+    for (const child of node.children) {
+      if (child.type === 'comment' || child.type === 'text') {
+        if (child.value.includes('\n')) {
+          eol = true
+        }
+
+        child.value = child.value.replace(
+          / *\n/g,
+          '$&' + state.indent.repeat(level)
+        )
+      }
+    }
+
+    /** @type {Array<RootContent>} */
+    const result = []
+    /** @type {RootContent | undefined} */
+    let previous
+
+    for (const child of node.children) {
+      if (padding(state, child) || (eol && !previous)) {
+        addBreak(result, level, child)
+        eol = true
+      }
+
+      previous = child
+      result.push(child)
+    }
+
+    if (previous && (eol || padding(state, previous))) {
+      // Ignore trailing whitespace (if that already existed), as we’ll add
+      // properly indented whitespace.
+      if (whitespace(previous)) {
+        result.pop()
+        previous = result[result.length - 1]
+      }
+
+      addBreak(result, level - 1)
+    }
+
+    node.children = result
+  }
+
+  /**
+   * @param {Array<RootContent>} list
+   *   Nodes.
+   * @param {number} level
+   *   Indentation level.
+   * @param {RootContent | undefined} [next]
+   *   Next node.
+   * @returns {undefined}
+   *   Nothing.
+   */
+  function addBreak(list, level, next) {
+    const tail = list[list.length - 1]
+    const previous = tail && whitespace(tail) ? list[list.length - 2] : tail
+    const replace =
+      (blank(state, previous) && blank(state, next) ? '\n\n' : '\n') +
+      state.indent.repeat(Math.max(level, 0))
+
+    if (tail && tail.type === 'text') {
+      tail.value = whitespace(tail) ? replace : tail.value + replace
+    } else {
+      list.push({type: 'text', value: replace})
+    }
+  }
+}
+
+/**
+ * @param {State} state
+ *   Info passed around.
+ * @param {Nodes | undefined} node
+ *   Node.
+ * @returns {boolean}
+ *   Whether `node` is a blank.
+ */
+function blank(state, node) {
+  return Boolean(
+    node &&
+      node.type === 'element' &&
+      state.blanks.length > 0 &&
+      state.blanks.includes(node.tagName)
+  )
+}
+
+/**
+ * @param {State} state
+ *   Info passed around.
+ * @param {Nodes} node
+ *   Node.
+ * @returns {boolean}
+ *   Whether `node` should be padded.
+ */
+function padding(state, node) {
+  return (
+    node.type === 'root' ||
+    (node.type === 'element'
+      ? state.head ||
+        node.tagName === 'script' ||
+        embedded(node) ||
+        !phrasing(node)
+      : false)
+  )
+}

lib/types.d.ts

@@ -0,0 +1,50 @@
+/**
+ * Configuration.
+ */
+export interface Options {
+  /**
+   * List of tag names to join with a blank line (default: `[]`);
+   * these tags,
+   * when next to each other,
+   * are joined by a blank line (`\n\n`);
+   * for example,
+   * when `['head', 'body']` is given,
+   * a blank line is added between these two.
+   */
+  blanks?: Array<string> | null | undefined
+  /**
+   * Whether to indent the first level (default: `true`);
+   * this is usually the `<html>`,
+   * thus not indenting `head` and `body`.
+   */
+  indentInitial?: boolean | null | undefined
+  /**
+   * Indentation per level (default: `2`);
+   * when `number`,
+   * uses that amount of spaces; when `string`,
+   * uses that per indentation level.
+   */
+  indent?: number | string | null | undefined
+}
+
+/**
+ * State.
+ */
+export interface State {
+  /**
+   * List of tag names to join with a blank line.
+   */
+  blanks: Array<string>
+  /**
+   * Whether the node is in `head`.
+   */
+  head: boolean
+  /**
+   * Whether to indent the first level.
+   */
+  indentInitial: boolean
+  /**
+   * Indentation per level.
+   */
+  indent: string
+}

lib/types.js

@@ -0,0 +1,2 @@
+// Note: types only.
+export {}

license

@@ -0,0 +1,22 @@
+(The MIT License)
+
+Copyright (c) Titus Wormer <[email protected]>
+
+Permission is hereby granted, free of charge, to any person obtaining
+a copy of this software and associated documentation files (the
+'Software'), to deal in the Software without restriction, including
+without limitation the rights to use, copy, modify, merge, publish,
+distribute, sublicense, and/or sell copies of the Software, and to
+permit persons to whom the Software is furnished to do so, subject to
+the following conditions:
+
+The above copyright notice and this permission notice shall be
+included in all copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED 'AS IS', WITHOUT WARRANTY OF ANY KIND,
+EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
+IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY
+CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
+TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
+SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.