Function Signature

js

rgbaToHexA(r: number, g: number, b: number, a?: number): string

Parameters

r (number): Red channel value (0–255).
g (number): Green channel value (0–255).
b (number): Blue channel value (0–255).
a (number, optional): Alpha value (0–1). Defaults to 1 (fully opaque).

Return Value

Returns an 8-digit HEX string (#rrggbbaa) where the last two characters encode the alpha channel.

js

rgbaToHexA(255, 102, 0, 1);
// "#ff6600ff"

rgbaToHexA(0, 170, 255, 0.5);
// "#00aaff80"

rgbaToHexA(0, 0, 0, 0);
// "#00000000"

Examples

js

// Fully opaque green
console.log(rgbaToHexA(34, 139, 34));
// "#228b22ff"

// Semi-transparent blue
console.log(rgbaToHexA(0, 0, 255, 0.25));
// "#0000ff40"

// Transparent black
console.log(rgbaToHexA(0, 0, 0, 0));
// "#00000000"

Error Handling

Values are automatically clamped: RGB is clamped between 0–255, and alpha is clamped between 0–1. Out-of-range values are adjusted silently.

Usage Notes

Always outputs lowercase HEX strings.
Useful for modern CSS and graphics APIs supporting 8-digit HEX.
For HEX without alpha, use rgbToHex instead.