export declare const EXPRESSION_REFERENCE = "Available variables inside `expr('{{ ... }}')`:\n\n- `$json` \u2014 current item's JSON data from the immediate predecessor node only\n- `$('NodeName').item.json` \u2014 access the output item from another node that is paired with the current item\n- `nodeJson(node, 'field.path')` \u2014 SDK helper equivalent to `expr('{{ $(\"NodeName\").item.json.field.path }}')`\n- `$input.first()` \u2014 first item from immediate predecessor\n- `$input.all()` \u2014 all items from immediate predecessor\n- `$input.item` \u2014 current item being processed\n- `$binary` \u2014 binary data of current item from immediate predecessor\n- `$now` \u2014 current date/time (Luxon DateTime). Example: `$now.toISO()`\n- `$today` \u2014 start of today (Luxon DateTime). Example: `$today.plus(1, 'days')`\n- `$itemIndex` \u2014 index of current item being processed\n- `$runIndex` \u2014 current run index\n- `$execution.id` \u2014 unique execution ID\n- `$execution.mode` \u2014 'test' or 'production'\n- `$workflow.id` \u2014 workflow ID\n- `$workflow.name` \u2014 workflow name\n\nString composition \u2014 variables MUST always be inside `{{ }}`, never outside as JS variables:\n\n- `expr('Hello {{ $json.name }}, welcome!')` \u2014 variable embedded in text\n- `expr('Report for {{ $now.toFormat(\"MMMM d, yyyy\") }} - {{ $json.title }}')` \u2014 multiple variables with method call\n- `expr('{{ $json.firstName }} {{ $json.lastName }}')` \u2014 combining multiple fields\n- `expr('Total: {{ $json.items.length }} items, updated {{ $now.toISO() }}')` \u2014 expressions with method calls\n- `expr('Status: {{ $json.count > 0 ? \"active\" : \"empty\" }}')` \u2014 inline ternary\n\nDynamic data from other nodes \u2014 `$()` MUST always be inside `{{ }}`, never used as plain JavaScript:\n\n- WRONG: `expr('{{ ' + JSON.stringify($('Source').all().map(i => i.json.name)) + ' }}')` \u2014 $() outside {{ }}\n- CORRECT: `expr('{{ $(\"Source\").all().map(i => ({ option: i.json.name })) }}')` \u2014 $() inside {{ }}\n- CORRECT: `expr('{{ { \"fields\": [{ \"values\": $(\"Fetch Projects\").all().map(i => ({ option: i.json.name })) }] } }}')` \u2014 complex JSON inside {{ }}\n\nItem flow semantics \u2014 choose the reference that matches the current item:\n\n- Use `$('NodeName').item.json.field` or `nodeJson(sourceNode, 'field')` when the current node needs the value from the same paired item produced upstream.\n- Do NOT use `.first()` or `$input.first()` for per-item data in a multi-item workflow. `.first()` always reads item 0, so every downstream item reuses the first value.\n- Use `.first()` only when the workflow genuinely needs one global first item, such as a single configuration row.\n- If an upstream value is needed after another node replaces item JSON, reference the upstream node explicitly with `$('Extract Data').item.json.field`; do not expect the value to still exist on `$json`.\n\nWhen `$json` is unsafe - use `nodeJson(node, 'path')` or `$('NodeName').item.json.path` instead:\n\n- AI Agent subnodes: memory, language model, parser, retriever, vector store, and tool subnodes do not have the same immediate predecessor context as a main-flow node.\n  WRONG: `sessionKey: expr('{{ $json.chatId }}')`\n  CORRECT: `sessionKey: nodeJson(telegramTrigger, 'message.chat.id')`\n- Multi-branch fan-in: if a node receives data after IF/Switch/Merge-style branching, `$json` only means the current incoming item and may not contain the source field you need.\n  WRONG: `expr('{{ $json.userId }}')`\n  CORRECT: `nodeJson(userLookup, 'user.id')`\n- Replacing nodes: if the current output no longer contains a field extracted earlier, read the earlier node directly.\n  WRONG: `expr('{{ $json.eventId }}')`\n  CORRECT: `nodeJson(extractEventId, 'eventId')`\n- Further-upstream data: if the value comes from any node other than the immediate main predecessor, reference that node explicitly.\n  WRONG: `expr('{{ $json.email }}')`\n  CORRECT: `nodeJson(formTrigger, 'body.email')`";