Scan fields

x-lt-scan makes a form field take a scan. While a claimed form is open and editable, a scan whose scheme a field accepts fills that field. A scan that no field accepts, and every badge scan, goes to the global scan pipeline as usual (see Scan codes).

Token	Placement	Purpose
x-lt-scan	Field	The schemes a field accepts and the values it expects
x-lt-scan-submit	Schema root	Submit once every required scan field holds a value

{
  "type": "object",
  "x-lt-scan-submit": true,
  "required": ["containerCode"],
  "properties": {
    "containerCode": {
      "type": "string",
      "title": "Container",
      "x-lt-scan": {
        "schemes": [14],
        "expect": ["metadata.containerCode", "envelope.offeredContainers"],
        "expect-error": "This item goes in {{expected}}."
      }
    },
    "parts": {
      "type": "array",
      "items": { "type": "string" },
      "x-lt-scan": { "schemes": [16], "expect": ["envelope.expected_upcs"], "multiplicity": "count" }
    }
  }
}

Field keys

Key	Meaning
schemes	The scan scheme versions the field accepts. Required
value	"target" (default) writes the scanned target; "code" writes the code as scanned
expect	Context paths (metadata.*, envelope.*, lookup.*, and so on) whose values the field accepts. A path that holds a list contributes every entry
expect-error	The message for a scan outside expect; {{expected}} lists what the field accepts. Default: Expected {{expected}}
multiplicity	Array fields: "count" admits a value as many times as expect lists it (a part expected twice takes two scans); otherwise each expected value is admitted once
prompt	Array fields: the instruction shown while the field is empty. Default: the field’s description

A scan replaces a string field’s value. An array field appends, up to maxItems. Manufacturer barcodes compare as GTINs, so a UPC-A matches its 14-digit form.

An array scan field reads as a checklist: its prompt while empty, n of N beside the label, and a remove control on each scanned value while the form is editable. N is what expect admits (each listing under multiplicity: "count", each distinct value otherwise), or maxItems, so the count and the admission check agree. A removed value is admitted again on the next scan.

Which field takes the scan

1. The focused field, when it accepts the scan’s scheme.
2. Otherwise the first field in x-lt-order that accepts it and has room.
3. Otherwise the first field that accepts it.

Expected values are checked on both sides

A scan outside expect shows an error directly under the field that refused it and leaves the field as it was. An accepted scan shows a confirmation in the same place. Either way the field scrolls into view. The shared validator runs the same check at submit, so a typed value outside expect is a field error in the form and a 422 from the API.

x-lt-scan-submit

At the schema root, true submits the form once every required scan field holds a value and the form validates. On a shared station the submit raises the usual badge prompt, so the motion is: scan the container into the open form, then scan your badge.