Write expressions in Duaer

Where a Duaer expression goes

In Duaer, switch a parameter from a fixed value to Expression, then write the expression. Drag a field from INPUT, or type it. Text outside the braces stays as text. The part inside the braces becomes the computed value.

Do not scatter a long reshape across many node parameters. Use Edit Fields (Set) to add fields, change fields, or drop fields, and let later nodes read the prepared data.

Read the current item

$json is the current item. When a webhook puts the payload on body, read the city like this:

{{ $json.body.city }}

{{ $json["body"]["city"] }} is the same path. Dots and brackets address the same field.

More than one JavaScript statement

When the expression needs several statements, wrap them in an immediately invoked function and return the value you want. Date math uses Luxon’s DateTime.

{{(() => {
  const end = DateTime.fromISO("2017-03-13");
  const start = DateTime.fromISO("2017-02-13");
  return end.diff(start, "months").toObject();
})()}}

Expressions in credential fields

Duaer can evaluate an expression in a credential field. It uses this execution’s data, including values earlier nodes already produced, such as a token from a webhook. Each execution evaluates on its own. A later run does not reuse the previous result.

Errors you will see

• Invalid JSON output: the value is not valid JSON, or it references a field this input does not have.
• The expression cannot find its data, or a node has not executed yet: run that step first. In a Code node, $("Node name").isExecuted tells you whether an earlier node has run.
• Invalid syntax: an extra dot or a missing bracket. {{ $("If").item.json. }} is invalid because of the trailing dot.