feat(compiler-core/runtime-core): show codeframe in runtime compile errors (#220)

packages/compiler-core/src/codeframe.ts

@@ -0,0 +1,37 @@
+const range: number = 2
+
+export function generateCodeFrame(
+  source: string,
+  start: number = 0,
+  end: number = source.length
+): string {
+  const lines = source.split(/\r?\n/)
+  let count = 0
+  const res = []
+  for (let i = 0; i < lines.length; i++) {
+    count += lines[i].length + 1
+    if (count >= start) {
+      for (let j = i - range; j <= i + range || end > count; j++) {
+        if (j < 0 || j >= lines.length) continue
+        res.push(
+          `${j + 1}${' '.repeat(3 - String(j + 1).length)}|  ${lines[j]}`
+        )
+        const lineLength = lines[j].length
+        if (j === i) {
+          // push underline
+          const pad = start - (count - lineLength) + 1
+          const length = end > count ? lineLength - pad : end - start
+          res.push(`   |  ` + ' '.repeat(pad) + '^'.repeat(length))
+        } else if (j > i) {
+          if (end > count) {
+            const length = Math.min(end - count, lineLength)
+            res.push(`   |  ` + '^'.repeat(length))
+          }
+          count += lineLength + 1
+        }
+      }
+      break
+    }
+  }
+  return res.join('\n')
+}

packages/compiler-core/src/index.ts

@@ -99,6 +99,7 @@ export {
 } from './errors'
 export * from './ast'
 export * from './utils'
+export * from './codeframe'
 export { registerRuntimeHelpers } from './runtimeHelpers'
 
 // expose transforms so higher-order compilers can import and extend them