Cannot request `svg` output format for `svg` source files

[sgarner]

Environment

ipx v3.0.3

Reproduction

n/a

Describe the bug

Requesting an SVG source file without specifying an output format is allowed — it returns the SVG file unmodified (or optimised, if SVGO is enabled).

But requesting an SVG source file and explicitly specifying svg as the output format produces a JPEG output file.

This is because other file types cannot be converted to SVG, so svg is not listed in SUPPORTED_FORMATS and unsupported formats are transformed to jpeg.

The logic ought to be amended so that SVG -> SVG is acceptable.

Additional context

The relevant logic is here:

ipx/src/ipx.ts

Lines 224 to 252 in af698d0

	const format =
	mFormat && SUPPORTED_FORMATS.has(mFormat)
	? mFormat
	: SUPPORTED_FORMATS.has(imageMeta.type || "") // eslint-disable-line unicorn/no-nested-ternary
	? imageMeta.type
	: "jpeg";
	// Use original SVG if format is not specified
	if (imageMeta.type === "svg" && !mFormat) {
	if (options.svgo === false) {
	return {
	data: sourceData,
	format: "svg+xml",
	meta: imageMeta,
	};
	} else {
	// https://github.com/svg/svgo
	const { optimize } = await getSVGO();
	const svg = optimize(sourceData.toString("utf8"), {
	...options.svgo,
	plugins: ["removeScriptElement", ...(options.svgo?.plugins || [])],
	}).data;
	return {
	data: svg,
	format: "svg+xml",
	meta: imageMeta,
	};
	}
	}

Logs