Objects with no `constructor` fails to render in tree mode

[Kyungmin Bae]

Code to reproduce

<script>
  import { JSONEditor } from 'svelte-jsoneditor';
</script>

<JSONEditor content={{json: Object.create(null)}} />

Cause

Object.create(null) creates an object with no constructor set.
estimateSerializedSize recurses json and tests if one is object with value.constructor.name === 'Object', throwing TypeError: Cannot read properties of undefined (reading 'name') on such objects.

svelte-jsoneditor/src/lib/utils/typeUtils.ts

Lines 9 to 13 in 278dac5

 export function isObject(value: unknown): value is Record<string, unknown> { 
   // note that we check constructor.name, not constructor === Object, 
   // so we can use objects created in a different JS realm like an iframe. 
   return typeof value === 'object' && value !== null && value.constructor.name === 'Object' 
 } 

(Related issue: #321)

Parse function of json-bigint creates object with Object.create(null), causing the error when used as a custom parser of jsoneditor.

[Jos de Jong]

Good point! There is a utility function isObject that tries to identify whether something is a plain object (and not a Date or Map or class or something). We'll have to refine that function to cater for this case.

[Jos de Jong]

Fixed now in v0.21.3