IBM Watson传感器数据格式化求助：拆分时间戳及Node-RED实现

Hey there! Since you're working with Node-RED and need to split that combined timestamp into separate date and time fields for IBM Watson, here's a straightforward solution tailored to your setup.

The most flexible way to handle this in Node-RED is with a Function node—it lets you write simple JavaScript to split the timestamp exactly how you need it.

• Drag a Function node from the palette into your flow, connecting it right after the node that outputs your sensor JSON data.

// Adjust the path below if your timestamp is stored elsewhere (e.g., msg.timestamp)
const rawTimestamp = msg.payload.timestamp;
const timestamp = new Date(rawTimestamp);

// Validate the timestamp to avoid errors downstream
if (isNaN(timestamp.getTime())) {
    node.error(`Invalid timestamp format: ${rawTimestamp}`, msg);
    return null; // Stop processing if the timestamp can't be parsed
}

// Split into date and time (ISO 8601 format, which works great for Watson and visualization tools)
msg.payload.date = timestamp.toISOString().split('T')[0]; // Outputs "YYYY-MM-DD"
msg.payload.time = timestamp.toISOString().split('T')[1].split('.')[0]; // Outputs "HH:MM:SS"

// Optional: Use locale-specific formats if needed
// msg.payload.date = timestamp.toLocaleDateString(); // e.g., "10/5/2024"
// msg.payload.time = timestamp.toLocaleTimeString(); // e.g., "14:30:45"

// Optional: Remove the original timestamp if you don't need it anymore
// delete msg.payload.timestamp;

return msg;

• Update the msg.payload.timestamp path to match where your actual timestamp lives in your JSON payload. For example, if it's stored directly in msg.timestamp, change the first line to const rawTimestamp = msg.timestamp;.
• Deploy your flow, send a test payload with your combined timestamp, and check the output. You’ll see new date and time fields in your payload, ready to send to IBM Watson.

If you prefer avoiding code, use a Change node with JSONata expressions:

1. Add a Change node to your flow.
2. Add a "Set" action:
   • Target: msg.payload.date
   • Value: $split($formatDateTime($toMillis(msg.payload.timestamp), "yyyy-MM-dd'T'HH:mm:ss"), "T")[0]
3. Add a second "Set" action:
   • Target: msg.payload.time
   • Value: $split($formatDateTime($toMillis(msg.payload.timestamp), "yyyy-MM-dd'T'HH:mm:ss"), "T")[1]

• Make sure your timestamp is in a format JavaScript’s Date() constructor can parse (e.g., ISO 8601 like "2024-10-05T14:30:45Z" or a Unix timestamp). If it’s a non-standard string, you’ll need to tweak the parsing logic slightly.
• The ISO 8601 date/time format we used is ideal for IBM Watson and most data visualization tools, as it’s universally recognized and avoids formatting conflicts.

内容的提问来源于stack exchange，提问作者user7499377