isBinary()

Defined in: utils.ts:84

Heuristically determines whether a file should be treated as binary.

Detection strategy:

1. Reads only the first sampleSize bytes (default: 8 KB).
2. Immediately returns true if a NULL byte (0x00) is found.
3. Computes the ratio of suspicious non-printable bytes. If the ratio exceeds suspiciousThreshold, the file is treated as binary.

Suspicious bytes:

• Control characters outside common whitespace
• Bytes < 7 or between 15–31 (excluding \t, \n, \r)

This approach is:

• Fast (does not read entire file)
• Safe for large workspace scans
• Reliable for common binary formats (PNG, JPEG, ZIP, etc.)

⚠️ This is a heuristic, not MIME detection. Some exotic encodings may bypass detection.

Parameters

filePath

string

Absolute path to file.

sampleSize?

number = 8192

Number of bytes to inspect from file start.

suspiciousThreshold?

number = 0.3

Ratio (0–1) above which file is considered binary.

Returns

Promise<boolean>

true if file appears binary; otherwise false.

Example

if (await isBinary("/path/to/image.png")) {
  return; // Skip scanning
}