Permanent Waring: .then() only accepts functions but was passed: [object Undefined], [object Undefined]

[jklimke]

Recently Plotly seems to call Promises with undefined lib.PromiseError that causes a warning.

plotly.js/src/lib/index.js

Line 414 in dc15177

.then(undefined, lib.promiseError);

It seems that lib.promiseError is always undefined instead of a handler function.

Plotly version 2.2.1

Backtrace (from webpacked source):

react_devtools_backend.js:2560 Warning: .then() only accepts functions but was passed: [object Undefined], [object Undefined]    at Object.push../node_modules/plotly.js/src/lib/index.js.lib.syncOrAsync (http://localhost:3000/packs/js/vendors~._node_modules_plotly.js_src_c-1038554188271ecaf605.chunk.js:3214:38)    at Object._doPlot (http://localhost:3000/packs/js/vendors~._node_modules_plotly.js_src_c-1038554188271ecaf605.chunk.js:8977:22)    at Object.newPlot (http://localhost:3000/packs/js/vendors~._node_modules_plotly.js_src_c-1038554188271ecaf605.chunk.js:9153:18)    at Object.react (http://localhost:3000/packs/js/vendors~._node_modules_plotly.js_src_c-1038554188271ecaf605.chunk.js:11158:24)