feat($compile): display line numbers for errors in the parser

#6338

Author: Kingwl

Diff for: src/compiler/parser/html-parser.js

@@ -9,7 +9,7 @@
  * http://erik.eae.net/simplehtmlparser/simplehtmlparser.js
  */
 
-import { makeMap, no } from 'shared/util'
+import { makeMap, no, splitLine } from 'shared/util'
 import { isNonPhrasingTag } from 'web/compiler/util'
 
 // Regular Expressions for parsing tags and attributes
@@ -53,11 +53,30 @@ function decodeAttr (value, shouldDecodeNewlines) {
   return value.replace(re, match => decodingMap[match])
 }
 
+function resolveLineNumbers (lines, start) {
+  let l = 0
+  let cur = 0
+  for (let i = 0, len = lines.length; i < len; ++i) {
+    const { line, linefeed = '' } = lines[i]
+    if (cur + line.length < start) {
+      cur += (line.length + linefeed.length)
+      l++
+    } else {
+      break
+    }
+  }
+  return {
+    line: l,
+    column: start - cur
+  }
+}
+
 export function parseHTML (html, options) {
   const stack = []
   const expectHTML = options.expectHTML
   const isUnaryTag = options.isUnaryTag || no
   const canBeLeftOpenTag = options.canBeLeftOpenTag || no
+  const lines = splitLine(html)
   let index = 0
   let last, lastTag
   while (html) {
@@ -243,7 +262,7 @@ export function parseHTML (html, options) {
     }
 
     if (!unary) {
-      stack.push({ tag: tagName, lowerCasedTag: tagName.toLowerCase(), attrs: attrs })
+      stack.push({ tag: tagName, lowerCasedTag: tagName.toLowerCase(), attrs: attrs, start: match.start })
       lastTag = tagName
     }
 
@@ -280,8 +299,9 @@ export function parseHTML (html, options) {
           (i > pos || !tagName) &&
           options.warn
         ) {
+          const { line, column } = resolveLineNumbers(lines, stack[i].start)
           options.warn(
-            `tag <${stack[i].tag}> has no matching end tag.`
+            `tag <${stack[i].tag}> has no matching end tag at line ${line} column ${column}.`
           )
         }
         if (options.end) {

Diff for: src/shared/util.js

@@ -304,3 +304,27 @@ export function once (fn: Function): Function {
     }
   }
 }
+
+/**
+ * split string with different linefeed.
+ */
+const linefeedRE = /\r\n|\n|\u2028|\u2029/
+export function splitLine (str: string): Array<Object> {
+  const lines = []
+  while (str) {
+    const line = linefeedRE.exec(str)
+    if (line) {
+      const linefeed = line[0]
+      const idx = line.index
+      lines.push({
+        line: str.substring(0, idx),
+        linefeed
+      })
+      str = str.substring(idx + linefeed.length)
+    } else {
+      lines.push({ length: str })
+      break
+    }
+  }
+  return lines
+}

Diff for: test/unit/modules/compiler/parser.spec.js

@@ -593,4 +593,29 @@ describe('parser', () => {
     expect(ast.children[1].isComment).toBe(true) // parse comment with ASTText
     expect(ast.children[1].text).toBe('comment here')
   })
+
+  it('should warn with line and column', () => {
+    parse(`
+      <div>
+        <span>
+          123
+      </div>
+    `, baseOptions)
+    expect(`tag <span> has no matching end tag at line 2 column 8.`).toHaveBeenWarned()
+  })
+
+  it('should warn with correct match', () => {
+    parse(`
+      <div>
+        <div>
+          123
+      </div>
+    `, baseOptions)
+    expect(`tag <div> has no matching end tag at line 1 column 6.`).toHaveBeenWarned()
+  })
+
+  it('should work with different linefeed', () => {
+    parse('<div>\n  <div>\r\n    <span>\u2028      123\u2029    </span>\n  </div>\n  <li>\n</div>', baseOptions)
+    expect(`tag <li> has no matching end tag at line 6 column 2.`).toHaveBeenWarned()
+  })
 })