Uncaught (in promise) Error: Unexpected error has occured during resolution of named resource 'c1'
at NameResolver._callee$ (https://unpkg.com/grimoirejs-preset-basic@1.9.23/register/grimoire-preset-basic.js:10388:39)
at tryCatch (https://unpkg.com/grimoirejs-preset-basic@1.9.23/register/grimoire-preset-basic.js:34319:40)
at Generator.invoke [as _invoke] (https://unpkg.com/grimoirejs-preset-basic@1.9.23/register/grimoire-preset-basic.js:34554:22)
at Generator.prototype.(anonymous function) [as throw] (https://unpkg.com/grimoirejs-preset-basic@1.9.23/register/grimoire-preset-basic.js:34371:21)
at rejected (https://unpkg.com/grimoirejs-preset-basic@1.9.23/register/grimoire-preset-basic.js:10273:40)
Uncaught (in promise) Error: Can not instanciate unknown geometry type custom
at GeometryFactory._callee$ (https://unpkg.com/grimoirejs-preset-basic@1.9.23/register/grimoire-preset-basic.js:9695:39)
at tryCatch (https://unpkg.com/grimoirejs-preset-basic@1.9.23/register/grimoire-preset-basic.js:34319:40)
at Generator.invoke [as _invoke] (https://unpkg.com/grimoirejs-preset-basic@1.9.23/register/grimoire-preset-basic.js:34554:22)
at Generator.prototype.(anonymous function) [as next] (https://unpkg.com/grimoirejs-preset-basic@1.9.23/register/grimoire-preset-basic.js:34371:21)
at https://unpkg.com/grimoirejs-preset-basic@1.9.23/register/grimoire-preset-basic.js:9658:71
at Promise (<anonymous>)
at __awaiter (https://unpkg.com/grimoirejs-preset-basic@1.9.23/register/grimoire-preset-basic.js:9638:12)
at GeometryFactory.instanciate (https://unpkg.com/grimoirejs-preset-basic@1.9.23/register/grimoire-preset-basic.js:9682:20)
at GeometryComponent._callee$ (https://unpkg.com/grimoirejs-preset-basic@1.9.23/register/grimoire-preset-basic.js:12097:48)
at tryCatch (https://unpkg.com/grimoirejs-preset-basic@1.9.23/register/grimoire-preset-basic.js:34319:40)
You should specify executing timing of the japascript as just after loading <body>. You can find that preference with clicking gear mark on javascript editor.
If you write JS code on the HTML panel it will not result in an error. However, if you write the code on the JS panel, it will result in an error.
https://jsfiddle.net/mp96ra1j/