Task: Simple file based key value store (GetKey)

n8n workflow JSON:
{"id":11,"name":"Storage: GetKey","nodes":[{"name":"On clicking 'execute'","type":"n8n-nodes-base.manualTrigger","position":[240,280],"parameters":{},"typeVersion":1},{"name":"Config","type":"n8n-nodes-base.functionItem","position":[420,280],"parameters":{"functionCode":"return {\n  file: '/home/node/.n8n/local-files' + item.file,\n  key: item.key,\n  default: item.default\n}"},"typeVersion":1},{"name":"Read Binary File","type":"n8n-nodes-base.readBinaryFile","position":[600,280],"parameters":{"filePath":"={{$json[\"file\"]}}"},"typeVersion":1,"continueOnFail":true,"alwaysOutputData":true},{"name":"BinaryToJSON","type":"n8n-nodes-base.moveBinaryData","position":[780,280],"parameters":{"options":{}},"typeVersion":1,"alwaysOutputData":true},{"name":"ReturnValue","type":"n8n-nodes-base.functionItem","position":[960,280],"parameters":{"functionCode":"const key = $node[\"Config\"].json[\"key\"]\nconst defaultValue = $node[\"Config\"].json[\"default\"]\n\nlet value\nif (item) {\n  value = item[key] || defaultValue\n} else {\n  value = defaultValue\n}\n\nreturn {\n  [ key ]: value\n}"},"typeVersion":1}],"active":false,"settings":{},"connections":{"Config":{"main":[[{"node":"Read Binary File","type":"main","index":0}]]},"BinaryToJSON":{"main":[[{"node":"ReturnValue","type":"main","index":0}]]},"Read Binary File":{"main":[[{"node":"BinaryToJSON","type":"main","index":0}]]},"On clicking 'execute'":{"main":[[{"node":"Config","type":"main","index":0}]]}}}