Function randStr

test/cssIdentifier.unittest.js:139–153

(/** @type {() => number} */ rng)

			"-_0123456789"
		];
		const randStr = (/** @type {() => number} */ rng) => {
			const len = (rng() * 40) | 0;
			const surrogateMode = rng() < 0.2;
			let out = "";
			for (let i = 0; i < len; i++) {
				if (surrogateMode) {
					// any BMP code unit, including lone surrogates 0xD800-0xDFFF
					out += String.fromCharCode((rng() * 0x10000) | 0);
				} else {
					const pool = POOLS[(rng() * POOLS.length) | 0];
					out += pool[(rng() * pool.length) | 0];
				}
			}
			return out;
		};

		it("escape/unescape never throw and round-trip on random input", () => {
			const rng = makeRng(0x12345678);