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Function Signature

async function maybeSecretFloat(
  key: string
): Promise<number | undefined>

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Parameters

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key
string
required
The environment variable name that points to the secret file path

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Returns

Promise<number | undefined> - The floating-point number from the secret file, or undefined if not found

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How It Works

This is the optional variant of secretFloat. It reads secrets from the filesystem without throwing errors when the file is missing:
  1. Checks if the environment variable key contains a file path
  2. If no path is set, defaults to /run/secrets/{key}
  3. Reads the file contents and parses it as a float
  4. Returns undefined if the secret file doesn’t exist (instead of throwing)
  5. Still throws an error if the file exists but contains an invalid number

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Difference from secretFloat

  • maybeSecretFloat: Returns undefined when the secret file is missing
  • secretFloat: Throws an error when the secret file is missing (unless a fallback is provided)
Use maybeSecretFloat for truly optional numeric secrets where absence is a valid state.

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Example

import { maybeSecretFloat } from "@nore/load-env"

// Returns undefined if the secret doesn't exist
export const RATE_LIMIT = await maybeSecretFloat("RATE_LIMIT")

const limit = RATE_LIMIT ?? 100.0 // Default to 100.0 if not set
console.log(`Rate limit: ${limit} requests per second`)

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Error Handling

Returns undefined if:
  • The secret file doesn’t exist
  • The file is empty
Throws an error if:
  • The file exists but cannot be parsed as a number (NaN)

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