Task: Simple file based key value store (WriteKey)

n8n workflow JSON:
{"id":12,"name":"Storage: WriteKey","nodes":[{"name":"On clicking 'execute'","type":"n8n-nodes-base.manualTrigger","position":[60,300],"parameters":{},"typeVersion":1},{"name":"Write Binary File","type":"n8n-nodes-base.writeBinaryFile","position":[420,740],"parameters":{"fileName":"={{$node[\"Config\"].json[\"file\"]}}","dataPropertyName":"=data"},"typeVersion":1},{"name":"Config","type":"n8n-nodes-base.functionItem","position":[600,300],"parameters":{"functionCode":"return {\n  file: '/home/node/.n8n/local-files' + item.file,\n  key: item.key,\n  value: item.value\n}"},"typeVersion":1},{"name":"Read Binary Files","type":"n8n-nodes-base.readBinaryFiles","position":[240,520],"parameters":{"fileSelector":"={{$json[\"file\"]}}"},"typeVersion":1,"continueOnFail":true,"alwaysOutputData":true},{"name":"SetKeyValue","type":"n8n-nodes-base.functionItem","position":[600,520],"parameters":{"functionCode":"const key = $node[\"Config\"].json[\"key\"]\nconst value = $node[\"Config\"].json[\"value\"]\nitem[key] = value\n\nreturn item;"},"typeVersion":1},{"name":"BinaryToJSON","type":"n8n-nodes-base.moveBinaryData","position":[420,520],"parameters":{"options":{}},"typeVersion":1,"alwaysOutputData":true},{"name":"JSONToBinary","type":"n8n-nodes-base.moveBinaryData","position":[240,740],"parameters":{"mode":"jsonToBinary","options":{}},"typeVersion":1},{"name":"SplitInBatches","type":"n8n-nodes-base.splitInBatches","position":[420,300],"parameters":{"options":{},"batchSize":1},"typeVersion":1},{"name":"Repeat","type":"n8n-nodes-base.if","position":[600,740],"parameters":{"conditions":{"boolean":[{"value1":"={{$node[\"SplitInBatches\"].context[\"noItemsLeft\"]}}","value2":true}]}},"typeVersion":1},{"name":"Done","type":"n8n-nodes-base.functionItem","position":[800,740],"parameters":{"functionCode":"console.log('Done!');\n\nreturn item;"},"typeVersion":1}],"active":false,"settings":{},"connections":{"Config":{"main":[[{"node":"Read Binary Files","type":"main","index":0}]]},"Repeat":{"main":[[{"node":"Done","type":"main","index":0}],[{"node":"SplitInBatches","type":"main","index":0}]]},"SetKeyValue":{"main":[[{"node":"JSONToBinary","type":"main","index":0}]]},"BinaryToJSON":{"main":[[{"node":"SetKeyValue","type":"main","index":0}]]},"JSONToBinary":{"main":[[{"node":"Write Binary File","type":"main","index":0}]]},"SplitInBatches":{"main":[[{"node":"Config","type":"main","index":0}]]},"Read Binary Files":{"main":[[{"node":"BinaryToJSON","type":"main","index":0}]]},"Write Binary File":{"main":[[{"node":"Repeat","type":"main","index":0}]]},"On clicking 'execute'":{"main":[[{"node":"SplitInBatches","type":"main","index":0}]]}}}