fix: make character positions for newlines the same as vscode (#112)

Author: DylanPiercey

.changeset/clean-months-cheat.md

@@ -0,0 +1,5 @@
+---
+"htmljs-parser": major
+---
+
+Switch character position offsets for newlines to be to similar to vscode. Previously the newline was counted as the first character of the line, now it is the last character of the previous line.

src/__tests__/main.test.ts

@@ -35,7 +35,7 @@ for (const entry of fs.readdirSync(FIXTURES)) {
               end: inputRange.end,
             }
           : inputRange;
-      const pos = parser.positionAt(range.start);
+      const pos = positionAt(range.start);
       partsByLine[pos.line].push({
         label,
         range,
@@ -60,6 +60,14 @@ for (const entry of fs.readdirSync(FIXTURES)) {
         }
       }
     };
+    const positionAt = (offset: number): Position => {
+      if (offset && lines.includes(offset + 1)) {
+        // Normalize lines to their first char.
+        return parser.positionAt(offset + 1);
+      }
+
+      return parser.positionAt(offset);
+    };
     const tagStack: Ranges.TagName[] = [];
     const parser = createParser({
       onError(range) {
@@ -187,23 +195,23 @@ for (const entry of fs.readdirSync(FIXTURES)) {
           linePrefix +
           read({
             start: 0,
-            end: lines[1],
+            end: lines.length > 1 ? lines[1] - 1 : src.length,
           })
         }`;
       } else {
         result += `\n${
           linePrefix +
           read({
-            start: lines[line] + 1,
-            end: lines[line + 1],
+            start: lines[line],
+            end: lines.length > line + 1 ? lines[line + 1] - 1 : src.length,
           })
         }`;
       }
 
       if (len) {
         const padding = " ".repeat(linePrefix.length - 3);
         parts.sort((a, b) => {
-          const delta = (a.pos.character || 1) - (b.pos.character || 1);
+          const delta = a.pos.character - b.pos.character;
           return delta === 0 ? b.range.start - a.range.start : delta;
         });
 
@@ -212,7 +220,7 @@ for (const entry of fs.readdirSync(FIXTURES)) {
 
         for (let i = 0; i < len; i++) {
           const part = parts[i];
-          const col = part.pos.character || 1;
+          const col = part.pos.character + 1;
           const delta = col - lastCol;
 
           if (delta > 0) {
@@ -234,15 +242,15 @@ for (const entry of fs.readdirSync(FIXTURES)) {
             }
           }
 
-          const column = pos.character || 1;
+          const column = pos.character;
 
-          if (prevPart && (prevPart.pos.character || 1) === column) {
+          if (prevPart && prevPart.pos.character === column) {
             label = `├${label}`;
           } else {
             label = `╰${label}`;
           }
 
-          label = `${columns.slice(0, column - 1)}${label}`;
+          label = `${columns.slice(0, column)}${label}`;
           result += `\n${padding + (prevPart ? `│  ${label}` : `╰─ ${label}`)}`;
         }
       }

src/util/util.ts

@@ -41,10 +41,10 @@ export function getPos(
 }
 
 export function getLines(src: string) {
-  const lines = [-1];
+  const lines = [0];
   for (let i = 0; i < src.length; i++) {
     if (src.charCodeAt(i) === CODE.NEWLINE) {
-      lines.push(i);
+      lines.push(i + 1);
     }
   }