fix: don't throw exception on invalid main attr (#109)

Callback with an error instead

Author: wraithgar

read-json.js

@@ -522,6 +522,10 @@ function final (file, data, log, strict, cb) {
 function fillTypes (file, data, cb) {
   var index = data.main ? data.main : 'index.js'
 
+  if (typeof index !== 'string') {
+    return cb(new TypeError('The "main" attribute must be of type string.'))
+  }
+
   // TODO exports is much more complicated than this in verbose format
   // We need to support for instance
 

test/fixtures/badmainnonstring.json

@@ -0,0 +1,8 @@
+{
+  "name": "invalid_main",
+  "main": [
+    "why is this a thing",
+    "this can't work"
+  ]
+}
+

test/main-non-string.js

@@ -0,0 +1,14 @@
+var tap = require('tap')
+var readJson = require('../')
+var path = require('path')
+var p = path.resolve(__dirname, 'fixtures/badmainnonstring.json')
+
+tap.test('non-string main entries', function (t) {
+  var logmsgs = []
+  const warn = (...msg) => logmsgs.push(msg)
+  readJson(p, warn, function (er, data) {
+    t.comment(logmsgs.map(msg => 'Warning: ' + msg.join(' ')).join('\n'))
+    t.match(er, new TypeError('The "main" attribute must be of type string.'))
+    t.end()
+  })
+})