Add optional support for source locations

readme.md

@@ -115,6 +115,11 @@ Type: `Boolean`
 Default: `false`   
 Description: *If set to true, self-closing tags will trigger the `onclosetag` event even if `xmlMode` is not set to `true`. NOTE: If `xmlMode` is set to `true` then self-closing tags will always be recognized.*
 
+### `sourceLocations`
+Type: `Boolean`
+Default: `false`
+Description: *If set to true, AST nodes will have a `location` property containing the `start` and `end` line and column position of the node.*
+
 ## License
 
 [MIT](LICENSE)

src/index.ts

@@ -1,5 +1,6 @@
 import {Parser, ParserOptions} from 'htmlparser2';
-import {Directive, Node, Options, Attributes} from '../types/index.d';
+import {Directive, Node, NodeTag, Options, Attributes} from '../types/index.d';
+import {LocationTracker} from './location-tracker';
 
 const defaultOptions: ParserOptions = {
   lowerCaseTags: false,
@@ -16,6 +17,7 @@ const defaultDirectives: Directive[] = [
 ];
 
 const parser = (html: string, options: Options = {}): Node[] => {
+  const locationTracker = new LocationTracker(html);
   const bufArray: Node[] = [];
   const results: Node[] = [];
 
@@ -92,7 +94,15 @@ const parser = (html: string, options: Options = {}): Node[] => {
   }
 
   function onopentag(tag: string, attrs: Attributes) {
-    const buf: Node = {tag};
+    const start = locationTracker.getPosition(parser.startIndex);
+    const buf: NodeTag = {tag};
+
+    if (options.sourceLocations) {
+      buf.location = {
+        start,
+        end: start
+      };
+    }
 
     if (Object.keys(attrs).length > 0) {
       buf.attrs = normalizeArributes(attrs);
@@ -104,6 +114,10 @@ const parser = (html: string, options: Options = {}): Node[] => {
   function onclosetag() {
     const buf: Node | undefined = bufArray.pop();
 
+    if (buf && typeof buf === 'object' && buf.location && parser.endIndex !== null) {
+      buf.location.end = locationTracker.getPosition(parser.endIndex);
+    }
+
     if (buf) {
       const last = bufferArrayLast();
 

src/location-tracker.ts

@@ -0,0 +1,39 @@
+import {Position} from '../types/index.d';
+
+export class LocationTracker {
+  private readonly source: string;
+  private lastPosition: Position;
+  private lastIndex: number;
+
+  constructor(source: string) {
+    this.source = source;
+    this.lastPosition = {
+      line: 1,
+      column: 1
+    };
+
+    this.lastIndex = 0;
+  }
+
+  getPosition(index: number): Position {
+    if (index < this.lastIndex) {
+      throw new Error('Source indices must be monotonic');
+    }
+
+    while (this.lastIndex < index) {
+      if (this.source.charCodeAt(this.lastIndex) === /* \n */ 10) {
+        this.lastPosition.line++;
+        this.lastPosition.column = 1;
+      } else {
+        this.lastPosition.column++;
+      }
+
+      this.lastIndex++;
+    }
+
+    return {
+      line: this.lastPosition.line,
+      column: this.lastPosition.column
+    };
+  }
+}

test/test-core.spec.ts

@@ -240,3 +240,55 @@ test('should be not converting html entity name', t => {
   const expected = ['‌ ©'];
   t.deepEqual(tree, expected);
 });
+
+test('should parse with source locations', t => {
+  const html = '<h1>Test</h1>\n<p><b>Foo</b></p>';
+  const tree = parser(html, {sourceLocations: true});
+  const expected = [
+    {
+      tag: 'h1',
+      content: ['Test'],
+      location: {
+        start: {
+          line: 1,
+          column: 1
+        },
+        end: {
+          line: 1,
+          column: 13
+        }
+      }
+    },
+    '\n',
+    {
+      tag: 'p',
+      content: [
+        {
+          tag: 'b',
+          content: ['Foo'],
+          location: {
+            start: {
+              line: 2,
+              column: 4
+            },
+            end: {
+              line: 2,
+              column: 13
+            }
+          }
+        }
+      ],
+      location: {
+        start: {
+          line: 2,
+          column: 1
+        },
+        end: {
+          line: 2,
+          column: 17
+        }
+      }
+    }
+  ];
+  t.deepEqual(tree, expected);
+});

types/index.d.ts

@@ -12,6 +12,7 @@ export type Directive = {
 
 export type Options = {
   directives?: Directive[];
+  sourceLocations?: boolean;
 } & ParserOptions;
 
 export type Tag = string | boolean;
@@ -23,6 +24,17 @@ export type NodeTag = {
   tag?: Tag;
   attrs?: Attributes;
   content?: Content;
+  location?: SourceLocation;
 };
 
 export type Node = NodeText | NodeTag;
+
+export type SourceLocation = {
+  start: Position;
+  end: Position;
+};
+
+export type Position = {
+  line: number;
+  column: number;
+};