fix: more friendly messages for non-string

Hoishin · Feb 14, 2018 · 58f8c19 · 58f8c19
1 parent 5200fbe
commit 58f8c19
Showing 1 changed file with 24 additions and 19 deletions.
diff --git a/index.js b/index.js
@@ -6,26 +6,31 @@ function parseJson (txt, reviver, context) {
   try {
     return JSON.parse(txt, reviver)
   } catch (e) {
-    const syntaxErr = e.message.match(/^Unexpected token.*position\s+(\d+)/i)
-    const errIdx = syntaxErr
-    ? +syntaxErr[1]
-    : e.message.match(/^Unexpected end of JSON.*/i)
-    ? txt.length - 1
-    : null
-    if (errIdx != null) {
-      const start = errIdx <= context
-      ? 0
-      : errIdx - context
-      const end = errIdx + context >= txt.length
-      ? txt.length
-      : errIdx + context
-      e.message += ` while parsing near '${
-        start === 0 ? '' : '...'
-      }${txt.slice(start, end)}${
-        end === txt.length ? '' : '...'
-      }'`
+    if (typeof txt !== 'string') {
+      const type = typeof txt === 'undefined' ? ' ' : ` the ${typeof txt} `
+      e.message = `Cannot parse${type}${String(txt)}`
     } else {
-      e.message += ` while parsing '${txt.slice(0, context * 2)}'`
+      const syntaxErr = e.message.match(/^Unexpected token.*position\s+(\d+)/i)
+      const errIdx = syntaxErr
+      ? +syntaxErr[1]
+      : e.message.match(/^Unexpected end of JSON.*/i)
+      ? txt.length - 1
+      : null
+      if (errIdx != null) {
+        const start = errIdx <= context
+        ? 0
+        : errIdx - context
+        const end = errIdx + context >= txt.length
+        ? txt.length
+        : errIdx + context
+        e.message += ` while parsing near '${
+          start === 0 ? '' : '...'
+        }${txt.slice(start, end)}${
+          end === txt.length ? '' : '...'
+        }'`
+      } else {
+        e.message += ` while parsing '${txt.slice(0, context * 2)}'`
+      }
     }
     throw e
   }