As informed by @Paul-Reed the change node has $moments() in the JSONata expression.
e.g.
[{"id":"c7fe2615.e38278","type":"inject","z":"8d22ae29.7df6d","name":"","props":[{"p":"payload"},{"p":"topic","vt":"str"}],"repeat":"","crontab":"","once":false,"onceDelay":0.1,"topic":"","payload":"20201015120000","payloadType":"str","x":220,"y":1960,"wires":[["e23e595e.a3d348"]]},{"id":"e23e595e.a3d348","type":"change","z":"8d22ae29.7df6d","name":"","rules":[{"t":"set","p":"payload","pt":"msg","to":"(\t $currentTime := $moment().tz('Europe/London').format();\t $duration := $moment(payload,'YYYYMMDDHHmmss').fromNow($currentTime);\t {\t \"current\": $currentTime,\t \"duration\": $duration\t }\t)\t\t","tot":"jsonata"}],"action":"","property":"","from":"","to":"","reg":false,"x":440,"y":1960,"wires":[["49952583.65b3fc"]]},{"id":"49952583.65b3fc","type":"debug","z":"8d22ae29.7df6d","name":"","active":true,"tosidebar":true,"console":false,"tostatus":false,"complete":"false","statusVal":"","statusType":"auto","x":650,"y":1960,"wires":[]}]
